Biology Archives - Page 4 of 8

April 9, 2020June 7, 2020

Whale shark

Sir Fish of the Stars.
Legacy of violence
reveals your true age.

The whale shark is the largest known fish species on the planet, with the longest specimen recorded at 18.8 meters. These gentle giants swim slowly through tropical waters, filter feeding on plankton and small fishes. No one is clear on how long-lived they are – like all sharks they lack the bony structures (otoliths) that are normally used to assess age in other fish species. Yet researchers now think they have the answer, and it lies in the legacy of the cold war.

Whale shark vertebrate have growth bands that increase as they age, rather like tree rings. The trouble is that without knowing how rapidly these bands form it is hard to use them to work out the age of a whale shark. Yet researchers have worked out a useful method of providing a scale for the growth bands by using the effects of nuclear weapons testing.

In the 1950s and 1960s nuclear bomb tests were carried out by countries on both sides of the Cold War, including in the atmosphere. The result of these tests is that the levels of the naturally occurring radioactive element carbon-14 temporarily increased, entering the food web – including whale shark vertebrate.

Ong et al. (2020) used radiocarbon assays of the growth bands of vertebrate from 20 whale sharks caught by the Taiwanese fishery before it was closed in 2007. They found the sampled whale sharks ranged in age from 15 to 50, and that growth bands appear to form annually. The importance of this is key to conservation efforts as understanding population structure is fundamental to understanding threats to the populations.

A note about ‘Whale shark’: Their size and nature mean that whale sharks are widely respected around the world, even featuring on the 100-peso note in the Philippines. Whale sharks are called ‘marokintana’ in Madagascar, meaning ‘many stars’ in reference to the white markings on their dark backs, whilst in Vietnam they are known as ‘ca ong’ – literally translated as ‘sir fish’.

Original research: http://dx.doi.org/10.3389/fmars.2020.00188

April 3, 2020April 3, 2020

Holdfast

Marine forests sway,
sheltering, pristine, unchanged.
For how much longer?

Giant kelp forests are some of the most diverse, productive and dynamic ecosystems on the planet. A marine algae (not a plant), giant kelp anchors itself to the seabed and grows up towards the surface, with some species growing up to 30-60 centimetres vertically a day to reach heights of 45 meters. Whilst typically found in temperate and polar coastal oceans, deep water kelp forests have been discovered in clear tropical waters where the sunlight can penetrate far enough below the water surface for the kelp to grow, potentially as far down as 200 meters.

Kelp forests are home to a vast number of species, from those living in the surface canopy to those on the seafloor. This makes them key areas to protect for species richness, much like rainforests and coral reefs. Yet many kelp forests are under threat due to marine pollution, water quality, kelp harvesting, overfishing, invasive species and climate change.

This makes the recent survey of kelp forests in southern South America heartening. Friedlander et al. (2020) re-surveyed 11 locations at the easternmost extent of Tierra del Fuego and compared their findings to surveys originally conducted in 1973. They found no differences in kelp densities or anchor diameter. Sea urchins, if not kept in check, can decimate kelp forests but the researchers also found no difference in sea urchin numbers. Additionally, comparisons of satellite imagery showed no long-term trends over the past 20 years.

It’s thought that the remoteness of the location has meant these kelp forests have been relatively unaffected by human disturbance, although increases in sea temperature as a result of climate change are likely to have an impact in the future.

A note about ‘Holdfast’ – The title refers to both the wish that kelp forests such as the one surveyed in this study persist and survive, and to the root-like mass that anchors kelp to the seafloor which is known as the kelp’s holdfast.

Original research: http://dx.doi.org/10.1371/journal.pone.0229259

March 6, 2020March 6, 2020

Aid pride

Got hearing aid shame?
No sense in letting age-pride
steal away your brain.

For many people the idea of needing a hearing aid is embarrassing, a sign of ageing that they don’t want to be reminded of or seen to need. Yet this shame may actually be harmful – a new study by Sarant et al. (2020) suggests that the use of a hearing aid may stave off cognitive decline.

The researchers assessed 99 adults aged between 60 and 84 before and after hearing aid use. After 18 months they found cognitive executive function (the higher level mental abilities used organise information, plan, and initiate and complete tasks) improved across the whole sample, especially in women.

Whilst sample sizes were small, the researchers also found that speech perception in quiet environments improved, as did participants’ self-reported quality of life and listening disability. This is an exciting development and, whilst further and larger studies are needed, it suggests that hearing aids may help to delay cognitive decline.

Further reading: http://dx.doi.org/10.3390/jcm9010254

February 13, 2020February 13, 2020

Climate Masting

Seed production up,
surely that’s a good thing, no?
Benefits declined.

Whilst the world stirs slowly into action to limit climate change, general consensus is that there will be some winners amongst the losers as temperatures rise. All organisms have their niches and changing environments will benefit some just as much they cost others.

Or at least that’s the simplistic take on the matter…

New research into plant masting – synchronous seed production – suggests that all isn’t as clear cut as that. The phenomenon of masting is beneficial to plants as the synchronicity “increases the efficiency of pollination and satiates predators” – sure predators will eat lots of seeds but the overwhelming numbers of seeds mean that large numbers aren’t eaten. It’s a bit like the synchronous emergence of some cicada species, which only emerge on mass every 13 or 17 years, with the gaps between emergence ensuring that predators aren’t reliant on the cicadas as a stable food source.

Bogdziewicz et al. (2020) looked at a 39 year-long masting dataset for the European beech and found that whilst climate warming increased seed production, the trees are actually losing out for three reasons:

1) Increased temperatures result in more consistent numbers of seed produced year-on-year – preventing the traditional boom and bust nature of seed production that helps to limit predator numbers.

2) Increased temperatures reduce synchronicity, resulting in less effective pollination.

3) Reduced seed production synchronicity means that predators aren’t overwhelmed by the sheer numbers of seeds available and are able to eat more seeds over a longer period of time.

All of this means that whilst the simple story suggests climate warning leads to increased seed production, the truth is more complex and instead those that actually benefit are those that eat the seeds.

Original research: https://doi.org/10.1038/s41477-020-0592-8

December 13, 2019December 18, 2019

Aye-Aye!

The northern monkey.
Never in need of a lift
with its pseudothumb.

The aye-aye is a curious primate found in Madagascar that has possibly the most unusual hands in the animal kingdom. Their hands are so elongated that they account for around 41% of their total length of the forelimb. The aye-aye’s long, bony third finger is its calling card – unique in the animal kingdom, it’s a specialised tool for getting grubs out of deep holes and probing for food whilst foraging.

Yet such specialisation can have costs, including weakening the ability of aye-ayes to grip. Hartstone-Rose & Dickinson et al. (2019) suggest that the aye-aye’s pseudothumb may have evolved to combat this disadvantage. The researchers found the pseudothumb has bony, cartilaginous and muscular features, suggesting that it enhances the aye-aye’s grip of smaller items such as thin branches.

A note about the sciku – Aye-ayes are lemurs and are not monkeys (they’re strepsirrhine primates). The sciku calls them northern monkeys because ‘aye’ is a common term in the north of England and in Scotland meaning ‘yes’, and ‘why-aye’ or ‘wey-aye’ are northern (mainly Geordie) terms for ‘well yes’ or ‘well, yes of course’. The term northern monkey is also a derogatory term in the UK for someone from the north of England (the counter of which is southern fairy).

Original research: https://doi.org/10.1002/ajpa.23936

September 12, 2019September 12, 2019

Tiny predator

Cambrian fossil,
your pincers – a coat of arms.
Ancient arachnid.

The Burgess Shale in the Canadian Rockies has some of the most complete and well preserved fossils found anywhere in the world, allowing researchers to gain huge insights into life millions of years ago during the middle Cambrian period.

Now a new species has been described that illuminates the early development of chelicerate – a group of over 115,000 species that contains spiders, scorpions and horseshoe crabs.

In their paper Aria & Caron (2019) describe the morphology of Mollisonia plenovenatrix, including robust but short chelicerae (pincers) that were located between the animal’s eyes, in front of its mouth. These are the predecessors of the pincers that spiders and scorpions use to kill, hold and cut their prey.

It’s likely that the species hunted close to the sea floor, using long walking legs and other sensory limbs to detect prey. The finding suggests that the origin of the chelicerate must be earlier in the Cambrian period and that the group must have rapidly expanded to fill an underutilised ecological niche.

A note about the sciku: For the sake of the poem I have simplified chelicerate to arachnids. Lead author Cédric Aria has described the pincers (chelicerae) as the ‘coat of arms’ of the chelicerate which felt suitably poetic.

Original research: http://dx.doi.org/10.1038/s41586-019-1525-4

September 5, 2019January 28, 2022

The Psychopharmacological Revolution

’50s to ’60s
use of new psychotropics
soars in both genders
by Dr Michael J. Leach.

Psychotropic drugs act on the central nervous system to elicit a range of therapeutic effects, such as improved sleep and anxiety relief.

Barbiturate psychotropics are older medicines with narrow therapeutic indices, meaning that there is little difference between beneficial and harmful doses. Actress Judy Garland is one of many people who has tragically died from a barbiturate overdose.

Non-barbiturate psychotropics such as benzodiazepines, meanwhile, are newer and safer alternatives to barbiturates for the treatment of psychological disorders. An example of a psychotropic that is widely used in modern society is the benzodiazepine diazepam, which was first marketed under the brand name Valium.

Historically, the Psychopharmacological Revolution of the 1950s and 1960s saw the introduction of a wide range of non-barbiturate psychotropics onto a growing global pharmaceutical market. There has been little research into the gender-specific, community-level use of psychotropic drugs over the Psychopharmacological Revolution of the 1950s and 1960s.

In order to shed light on the origins of Australia’s relatively high modern-day consumption of psychotropics, my colleague and I conducted a study to explore gender-specific volumes of psychotropic dispensing at a Melbourne pharmacy during the 1950s and 1960s. This original research has been published in the peer-reviewed journal Pharmaceutical Historian.

In this study, I sourced data on the name of medicine dispensed, dispensing date during 1954 or 1961, and patient gender from a set of old prescription books that were kept at a community pharmacy in the inner Melbourne suburb of Toorak. I cross-referenced the dataset with historical pharmacy reference books to classify each medicine into one of the following mutually exclusive categories: barbiturate psychotropics, non-barbiturate psychotropics, and non-psychotropic medicines. After collecting data and classifying each medicine, I calculated the number of prescriptions dispensed in each year and adjusted for the size of the population residing in the surrounding local government area.

The study results indicated that twice and 1.7 times as many medicines were dispensed to females than to males during 1954 and 1961, respectively. Such gender differences were evident across all three categories of dispensed medicines: barbiturate psychotropics, non-barbiturate psychotropics, and non-psychotropic medicines. There was also a pronounced shift in psychotropic dispensing from the older, more dangerous barbiturates (77% in 1954; 38% in 1961) to newer, safer non-barbiturate psychotropics (23% in 1954; 62% in 1961). The extent of this shift over time to newer, safer psychotropics was similar in both genders.

Original research: Gender differences in psychotropic medicine dispensing at a pharmacy in Melbourne, Australia, 1954 and 1961 by Michael J. Leach and Rebecca Kippen.

Michael Leach (@m_jleach) is an Australian health researcher, biostatistician, and poet with a PhD in Pharmacoepidemiology and a passion for health humanities. Examples of his science poems are online here: https://imagesofhealth.wordpress.com/.

If you enjoyed this sciku, check out Michael’s other sciku ‘Quality of Life at Seven Years Post-Stroke‘ and ‘Drug-Induced Hip Fractures‘, ‘The Core Correlate of Covid-19 Vaccine Acceptance’, ‘The Early Impacts of COVID-19 on Australian General Practice‘, ‘The Burden of Bushfire Smoke‘, and ‘Australian Science Poetry‘ with science communicator Rachel Rayner.

August 29, 2019August 29, 2019

Spreading

Tiger mosquito,
spreading northwards, adapting.
Deadly time capsules.

Many mosquito species struggle to survive at low temperatures, preventing their spread into cooler climates and thus limiting the spread of diseases carried by the mosquitoes. Yet new research by Medley et al (2019) suggests that some mosquito species may be able to adapt part of their reproductive cycle to survive cold winters.

The Asian tiger mosquito is a vector for a number of pathogens, including Zika and dengue viruses. The species first arrived in the USA in Texas in 1985 and today the current range extends as far north New Jersey.

How has this tropical and sub-tropical species managed to survive the temperate conditions?

The secret lies with a process called diapause – a type of animal dormancy where development is delayed in response to unsuitable environmental conditions such as cold winters.

In the Asian tiger mosquito, the length of day or night (photoperiodism) can induce egg diapause – as the days get shorter with the approach of winter eggs become dormant and only start developing again once the days start to lengthen and temperatures are likely to be more suitable for the species.

In the new study the researchers found that northern diapause eggs survive northern winters a lot better than southern diapause eggs, but both northern and southern diapause eggs survive southern winters the same as each other. The research demonstrates the species adapting to colder conditions as it expands northwards over a period of around 30 years. Not only have northern populations adapted to northern climes by producing more eggs but those eggs are adapted to survive the northern winters better too.

Original research: https://doi.org/10.1111/1365-2664.13480

August 16, 2019August 16, 2019

Pickled – Not Pickled

Hidden, protected.
Ancient bird beneath acid,
DNA preserved.

DNA from extinct species can be hard to get – obtaining bone or tissue samples is tricky and degradation of those samples over time can result in vast swathes of the genome missing or heavily fragmented.

Yet, as a new study by Oswald et al (2019) suggests, there are circumstances where samples can be remarkably preserved across hundreds and even thousands of years.

The study used bones found in Sawmill Sink, a blue hole in the Bahamas. The Sawmill Sink has a top layer of fresh water, a hydrogen sulfide layer and then a bottom layer of saltwater. The hydrogen sulfide layer forms a barrier that limits UV light and oxygen from getting to the lower saltwater. As a result, the various bones found on floor of the blue hole are remarkably well preserved.

Oswald et al (2019) were able to recover a nearly complete mitochondrial genome from a 2,500 year old bone of an extinct bird species – Caracara creightoni. Genetic analysis of the ancient DNA suggests that the species is sister to a clade containing the Northern Crested Caracara and the Southern Crested Caracara, birds of prey in the Falconidae family found in Central and South America. The work highlights the huge potential for similarly recovered fossils to illuminate our understanding of species and populations in the past.

The title of this sciku is Pickled – Not Pickled. This refers to the hydrogen sulfide layer in Sawmill Sink which forms sulfuric acid where it comes into contact with the fresh water layer above, making it extremely hard for divers to get through and discover the bones beneath. Whilst the bones themselves were not in the sulfuric acid, they were preserved by it making them in essence pickled whilst not actually being pickled.

Original research: http://dx.doi.org/10.1016/j.ympev.2019.106576

August 9, 2019August 9, 2019

Amid fields of rubble

Seamounts amid fields
of rubble, scars and lost gear.
A glimmer of hope.

Seamounts are underwater mountains that rise at least 1,000 meters above the seafloor with their peaks hundreds or even thousands of meters underwater. Seamounts are often thriving areas of marine life, based around high levels of plankton and deep-sea corals.

However the fishing practice of trawling can decimate these areas, destroying corals and causing huge population crashes in the species that depend on them. Deep-sea coral growth rates can be as little as micrometres a year meaning that recovery, if possible, could be very slow. As a result it’s unknown whether protecting areas damaged by trawling is worthwhile or whether once lost these deep-sea communities are unlikely to recover.

New research by Baco et al. (2019) sheds comforting light on this dimly known area. Whilst little evidence supports seamount recovery over 10 years, their study examined recovery following 30-40 years protection from trawling. Encouragingly many of the sites surveyed showed multiple signs of recovery, including coral regrowth and higher levels of animal life compared to areas still being trawled. The research is clear and much needed evidence to support continued seamount protection efforts.

Author’s note: I thought that the research study’s title was too poetic to improve upon so used part of it in this sciku. The full title is ‘Amid fields of rubble, scars, and lost gear, signs of recovery observed on seamounts on 30- to 40-year time scales’ by Amy R. Baco, E. Brendan Roark and Nicole B. Morgan.

Original research: http://dx.doi.org/10.1126/sciadv.aaw4513

July 18, 2019July 18, 2019

Shrimp molting by Prof Hortense Le Ferrand

Hiding, weak and soft,
Mantis Shrimp matures and grows,
Preparing attack.
by Prof Hortense Le Ferrand

The Mantis Shrimp is an extraordinary animal in many ways. One of its striking features is its dactyl club: this is a biomaterial that is so hard and tough that it uses it to dismantle crabs and break seashells. But the Mantis Shrimp also grows by molting: during this process, it discards its club, and builds a new one.

In the paper by Amini et al (2019), the club of the Mantis was dissected during its maturation, from day zero to one month. It was observed that a thin membrane, initially folded into a cavity at the centre of the “old” club got inflated, before slowly being converted into the hard deadly appendage. The Mantis remained hidden in its nest until the biomineralization completed and the extraordinary mechanical properties of the club got recovered.

Original research: https://doi.org/10.1073/pnas.1816835116

Dr Hortense Le Ferrand is an Assistant Professor at Nanyang Technical University, Singapore. Hortense’s interests are on the fabrication and design of novel materials and systems inspired by nature. Check out her earlier sciku ‘Closing the Trap’ here.

July 12, 2019July 12, 2019

Whale strike

To avoid striking
whales, great creatures of the sea,
use the app. Impact!

Blue whales can be injured or killed in collisions with ships, particularly in regions where migration routes cross shipping lanes. Yet because they travel huge distances, predicting where whales will be at any given time is difficult. However, now research by Abrahms et al (2019) suggests that statistical modelling techniques may be able to help.

The researchers used satellite tracking data from 104 blue whales across 14 years along with daily information on three-dimensional oceanic habitats to model the whales’ daily distribution. By using an ensemble modelling approach they were able to produce daily, year-round predictions of blue whale habitat suitability in the Californian Current Ecosystem.

The statistical approach allows the researchers to quantify the spatial and temporal distribution of exposure to ship strike risk within shipping lanes in the Southern California Bight. The researchers plan on converting this approach into a downloadable app which would alert ships to the risks of whale collision and could recommend alternative shipping lanes or vessel slow-downs.

It’s a truly fascinating piece of research that seems likely to have a huge impact upon a real-world problem – research at its best.

The sciku also includes a line from Mr Scruff’s truly excellent track ‘Shanty Town’ from his ‘Keep It Unreal’ album released in 1999. The full line is ‘Whales! Great creatures of the sea! Please listen to me!’ It’s well worth checking out!

Original research: http://dx.doi.org/10.1111/ddi.12940

May 17, 2019May 17, 2019

Indigenous Engagement

The benefits of
indigenous engagement:
Ethics and Science.

Local knowledge and an awareness of local context can be integral to conducting a variety of research. However, one thing that’s less often considered is the impact of the diversity of the research team itself.

Conservation research by Ward-Fear et al (2019) into the impact of cane toads on yellow-spotted monitor lizards in Australia has unintentionally produced evidence of the scientific benefits of collaborating with local indigenous people.

Large cane toads are spreading through tropical Australia but are fatally toxic if eaten by yellow-spotted monitor lizards. Ward-Fear et al (2016) trained lizards with smaller, non-lethal cane toads and then compared the survival rates of trained and non-trained lizards in the wild over an 18 month period. They found that trained lizards had a greater survival rate than non-trained lizards, suggesting that the training helped the lizards to avoid eating the larger toxic cane toads.

Yet their study also revealed the importance of researcher diversity. In monitoring the population of lizards over 18 months, the research team included western scientists (professional, nonindigenous ecologists) and indigenous rangers (Australian-Aboriginal Traditional Owners of the region).

The indigenous rangers saw lizards from a greater distance, in more dense vegetation, under poorer light levels, and more frequently when the lizard was stationary. Additionally, when assessing the behavioural traits of the lizards, those that were spotted by the indigenous rangers were found to be more shy. What’s more, the ranger caught lizards appeared to benefit more from the training against the toxic cane toads.

All this highlights the importance of cultural diversity within research teams and in particular shows that indigenous collaboration can be utterly crucial for conservation efforts.

Original research:

Training of predatory lizards reduces their vulnerability to invasive toxic prey: https://doi.org/10.1098/rsbl.2015.0863

Collaboration with indigenous peoples can alter the outcomes of conservation research: http s://doi.org/10.1111/conl.12643

May 10, 2019May 10, 2019

Adaptation by Prof Fred W. Allendorf

Survive, reproduce
Mendel rules, pass on your genes
That’s adaptation
by Prof Fred W. Allendorf

Natural selection is one of the primary mechanisms of evolution. Those individuals with higher survival and greater reproductive success are more successful at passing on their genes to future generations. This brings about adaptation which increases the fitness of individuals in future generations.

Further reading: A brief history of the genetic theory of adaptation by H. Allen Orr (2005): http://dx.doi.org/10.1038/nrg1523

Prof Fred W. Allendorf is Regents Professor of Biology Emeritus at the University of Montana. His primary scientific interest is the application of population genetics to conservation biology. He is senior author of the book Conservation and the Genetics of Populations. Check out Fred’s other sciku on Genetic Drift, Inbreeding Depression and Gene Flow.

April 11, 2019April 11, 2019

Supine Risks

Supine position,
dreaming towards tragedy.
The risk of stillbirth.

New research has found that the risks of stillbirth are higher when the mother falls asleep lying on her back. Cronin et al (2019) analysed sleeping position and resulting birth success. Whilst no difference was found between going-to-sleep on the left or right side, the researchers found evidence that the supine going-to-sleep position is a contributing factor for late stillbirth. In fact, they suggest that if every pregnant woman of 28 weeks gestation and beyond settled to sleep on her side the number of late stillbirths could be reduced by 5.8%.

Original research: http://dx.doi.org/10.1016/j.eclinm.2019.03.014

April 5, 2019January 28, 2022

Drug-Induced Hip Fractures

psychoactive drugs
flood and fog brains soon before
falls and hip fractures
by Dr Michael J. Leach

There is an inherent poetry to pharmacy whereby medicines can help people through intended beneficial effects and harm people through unintended adverse events, including side effects and drug-drug interactions. It is crucial for prescribers to carefully weigh up the risks and benefits of treatment whenever a new medicine is considered for any given patient. As the modern world has an aging population, there have been rises in frailty, multiple morbidities (i.e. multimorbidity), and multiple medicine use. Multiple medicine use can be defined in terms of polypharmacy, which denotes the concurrent use of five or more drugs, and hyper-polypharmacy, which denotes the concurrent use of ten or more drugs. The increasing prevalence of polypharmacy and hyper-polypharmacy means that, in modern society, there is high potential for harmful side effects and drug-drug interactions.

Psychoactive medicines are examples of drugs that have unfavourable side effects and that can interact with one another to cause harm. Psychoactive medicines act on the central nervous system in different ways to elicit therapeutic and adverse effects. The main types of psychoactive medicines are antidepressants, antipsychotics, benzodiazepines, benzodiazepine-related drugs, opioid analgesics, anticholinesterases, antiepileptics, and anti-Parkinson medicines. A common side effect across all these psychoactive medicines is sedation. While treatment with benzodiazepines, benzodiazepine-related drugs, and antipsychotics may be aimed at helping people to relax or sleep at night, the sedative effect can still be harmful when there is unwanted daytime sedation or oversedation. The sedative effects of psychoactive medicines likely explain why these drugs increase the risk of falls and fractures, especially in older, frailer individuals. Furthermore, when any one psychoactive medicine is taken with another psychoactive medicine, there is an increased sedative burden on the patient. This increased sedative burden can place people at an even greater risk of falls and fractures.

Pharmacoepidemiology is the population-level study of medicine use. In original research conducted as part of my PhD in Pharmacoepidemiology, I used a number of study designs and statistical methods to quantify the risk of hip fracture following psychoactive medicine use in older people. I focused on particular types of psychoactive medicines (e.g. antipsychotic drugs and selective serotonin reuptake inhibitor [SSRI] antidepressants) used individually and in combination with one another. The risk of hip fracture was increased for a range of psychoactive medicines, most notably when they were used concurrently. This research is relevant to real world medical practice because the risk factors identified are potentially modifiable. If prescribers better understand the risks associated with psychoactive medicine use, then they can make more informed prescribing decisions and de-prescribe psychoactive medicines where appropriate. Older patients, their carers, and their family members, as well as nursing home staff, would also benefit from better understanding the significant risk posed by the use of psychoactive medicines.

The pharmacoepidemiological studies that make up my PhD thesis have been published in peer-reviewed journals and are available online:

Leach MJ, Pratt NL, Roughead EE. The risk of hip fracture due to mirtazapine exposure when switching antidepressants or using other antidepressants as add-on therapy. Drugs – Real World Outcomes. 2017; 4(4): 247-255. http://dx.doi.org/10.1007/s40801-017-0120-y

Leach MJ, Pratt NL, Roughead EE. The risk of hip fracture in older people using selective serotonin reuptake inhibitors and other psychoactive medicines concurrently: a matched case-control study in Australia. Drugs – Real World Outcomes. 2017; 4(2): 87-96. http://dx.doi.org/10.1007/s40801-017-0107-8

Leach MJ, Pratt NL, Roughead EE. Psychoactive medicine use and the risk of hip fracture in older people: a case-crossover study. Pharmacoepidemiology and Drug Safety. 2015; 24(6): 576-582. https://doi.org/10.1002/pds.3785

Leach MJ, Pratt NL, Roughead EE, Hayward K, Jenkins N. Medicine use among the elderly before and after hip fracture. Australian Journal of Pharmacy. 2014; 95(1125): 72-74. [A secondary publication arranged by the original publisher]. Available here.

Leach MJ, Pratt NL, Roughead EE. Medicine use among older Australians before and after hip fracture. Journal of Pharmacy Practice and Research. 2013; 43(4):265-268. https://doi.org/10.1002/j.2055-2335.2013.tb00271.x

If you enjoyed this sciku, check out Michael’s other sciku ‘Quality of Life at Seven Years Post-Stroke‘ and ‘The Psychopharmacological Revolution‘, ‘The Core Correlate of Covid-19 Vaccine Acceptance’, ‘The Early Impacts of COVID-19 on Australian General Practice‘, ‘The Burden of Bushfire Smoke‘, and ‘Australian Science Poetry‘ with science communicator Rachel Rayner.

March 19, 2019March 19, 2019

Astonishing carrier

Angolan spider –
astonishing carrier.
What is your horn for?

A new species of horned baboon spider has been described that has a soft horn on its back, unlike any spider previously found in the world. The species was found in Angola and Midgley and Engelbrecht (2019) have named it Ceratogyrus attonitifer – its name being a combination of the Latin for astonishment (attonit-) and carrier (-fer). The purpose of the large and soft horn on the spider’s back is currently completely unknown.

Original research: http://dx.doi.org/10.3897/afrinvertebr.60.32141

March 8, 2019May 10, 2019

Gene flow by Prof Fred W. Allendorf

Move away from home
Find a mate and reproduce
That is called gene flow
by Prof Fred W. Allendorf

Gene flow is the movement of alleles or genes from one population to another (Slatkin, 1987). Gene flow is crucial in reducing the harmful effects of genetic drift and inbreeding depression in populations. As global change, habitat destruction, and fragmentation rapidly progress, many natural populations are becoming smaller, more isolated, and more affected by inbreeding depression. However, Sewall Wright (1951) demonstrated that even very small amounts of gene flow are sufficient to avoid the harmful effects of genetic drift and inbreeding within local populations.

Original research:

Slatkin, M. 1987. Gene flow and the geographic structure of natural populations. Science 236: 787-792.

Wright, S. 1951. The genetical structure of natural populations. Annals of Eugenics 15: 323-354.

Prof Fred W. Allendorf is Regents Professor of Biology Emeritus at the University of Montana. His primary scientific interest is the application of population genetics to conservation biology. He is senior author of the book Conservation and the Genetics of Populations. Check out Fred’s other sciku on Genetic Drift, Inbreeding Depression and Adaptation.

January 24, 2019January 24, 2019

A body projects by Prof Tania Douglas

A body projects
to a model of others
and finds its own shape
by Tania Douglas

Reyneke et al (2018) review the state of the art in 3D reconstruction of bone from 2D images, based on deformable models. Such reconstructions are useful in a variety of clinical applications such as surgery planning and postoperative evaluation, and implant and prosthesis design.

Original research: https://doi.org/10.1109/RBME.2018.2876450

Prof Tania Douglas is the South African Research Chair in Biomedical Engineering & Innovation at the University of Cape Town, South Africa. You can follow her on Twitter under the handle @tania_douglas

January 11, 2019January 11, 2019

Armyworms

Armyworms. Crop pests.
Inflict losses with our help.
Where will you strike next?

Crop pests cause vast economic losses worldwide, having a huge impact on the livelihoods of some of the most vulnerable populations. Originally from the Americas, the fall armyworm recently spread to sub-Saharan Africa, resulting in estimates of 20 to 50% maize yield losses. The armyworm appears to have arrived in sub-Saharan Africa as a result of passenger flights from America and has spread widely across the continent in only a couple of years.

Research by Early et al (2018) has considered where the pest might spread to next. By considering the armyworm’s life-history, current trade and transportation routes and the climates of countries that currently have populations of armyworms, the researchers were able to forecast the most likely next steps for this spreading species. In particular, the researchers highlight that the climactic conditions of South and Southeast Asia and Australia make these regions susceptible to invasion, with Australia, China, India, Indonesia, Malaysia, Philippines and Thailand the most vulnerable.

Original research: https://doi.org/10.3897/neobiota.40.28165

December 7, 2018December 7, 2018

Spider milk

Unexpected milk –
not a mammalian trait?
Lactating spider.

Caring mothers aren’t the first thing that spring to mind when you think about spiders. Yet plenty of evidence exists of female spiders providing food for their young and protecting their offspring. A recent and very surprising example of arachnid maternal care comes from a species of ant-mimicking jumping spider.

Chen et al (2018) observed female spiders secreting a nutritious milk-like substance, which the offspring first consume from the floor of the nest and once they are a bit older directly from the mother herself. Through a careful set of experiments the researchers found that the spiderlings are entirely dependent on this ‘milk’ for survival, and that there are still huge survival benefits to it even once they are old enough to forage independently.

Milk provision was once seen as an exclusively mammalian trait but this research adds to growing evidence that the practice is more widespread across animal taxa than previously thought.

Original research: http://dx.doi.org/10.1126/science.aat3692

November 29, 2018November 29, 2018

Ensnared

Poor social spider.

Ensnared, building its own tomb.

Parasitoid wasp.

Parasitoid wasps are known to lay eggs on their victims which are then consumed by the hatching larvae. Some species will even paralyse their victim and place them in a nest to be eaten alive by their offspring. Yet behaviour observed by Fernandez-Fournier et al (2018) has revealed a wasp species that behaves even more disturbingly.

Adult Zatypota sp. wasps were found to target a species of social spider that lives in a colony web and rarely leaves it. The wasps lay their eggs on the abdomen of the spider and when the larvae hatches it attaches to the spider. The larvae influences the spider to then leave its colony and spin a cocoon web in which the spider then waits until the larvae finally kills it. Its meal consumed, the larvae then spins a pupal cocoon within the protection of the outer cocoon web and a few days later emerges as an adult.

The results reveal that the spider is manipulated into performing unusual behaviours, since such social spiders rarely leave their colony and the cocoon web is a complete different form of web. The infected spider makes its own tomb before being eaten alive within it.

Original research: http://dx.doi.org/10.1111/een.12698

November 7, 2018November 7, 2018

Domino effect

Domino effect.

Ocean-behaviour-hookworms

lead to seal pup deaths.

The web of life, food chains, ecological balance – there are a lot of terms that indicate how interlinked ecosystems are. A recent, tragic example of this is how a rise in ocean temperatures can indirectly result in increased seal pup death from hookworm infection.

Seguel et al (2018) found that sea temperatures influenced the survival of South American fur seal pups. Sea temperatures effect wind patterns and ocean currents, changing the abundance of nutrients and as a result fishes. Higher sea temperatures resulted in lower fish abundance, meaning that fur seal mothers needed to spend more time at sea feeding, consequentially spending less time with their pups. The reduced maternal care led to lower pup growth rates and a less effective immune system, making the fur seal pups more susceptible and less likely to successfully fight off hookworm infection.

Original research: http://dx.doi.org/10.7554/eLife.38432

October 31, 2018October 31, 2018

Small and spherical

Small and spherical,

the eggs of forest blue tits.

Urban differences.

Populations of many species live in different environments that provide varied resources and have differing selection pressures. Research by Bańbura et al (2018) investigated the eggs of blue tits living in a forest environment compared to a nearby urban park.

The researchers found that urban-dwelling blue tits produced eggs that were on average 5% larger than their forest-dwelling counterparts, and the urban eggs were less spherical as well. These differences are potentially the result of blue tit diets in each environment – the forest is caterpillar-rich but calcium-poor whilst the urban park is the opposite, with 5-6 times the density of snails which have calcium-rich shells. The smaller, rounder forest egg shape requires less calcium compared to the less spherical urban egg shape.

Original research: http://dx.doi.org/10.1186/s12983-018-0279-4

October 24, 2018October 24, 2018

Wild, rural, urban

Mammal density

wild, rural, urban – the same.

Rocking the suburbs.

Urban development encroaches on natural spaces, reducing and altering animal habitats. A consequence of this is that many species have evolved to live around humans, although developed areas are thought to have low species diversity and abundance.

Yet research by Parsons et al (2018) in coordination with citizen scientist volunteers suggests this might not be the case. Using camera traps placed in areas of varying development (from wild to urban) and scale (from forests to yards) the researchers found that mammals were found in similar or higher levels of abundancy and species richness in developed areas compared to wild areas. The research highlights the need to conserve wild areas and preserve green spaces within cities.

The keen eyed may spot that the final line of this sciku is a reference to Ben Folds’ first solo album ‘Rockin’ the Suburbs’, released in 2001.

Original research: https://doi.org/10.7554/elife.38012.001

October 11, 2018October 11, 2018

Absentee parents

Absentee parents.

Selection pressure leads to

self-sufficiency.

Parents invest in the survival of their offspring to differing amounts across the animal kingdom. Some parents provide for their young until they reach independence, whilst in other species the parents are absent from birth onwards.

The burying beetle shows a mix of these tendencies. The parents use small dead mammals and other vertebrates as edible nests for their young. The larvae hatch and enter the carcass, while the parents may help the larvae enter the nest by biting small incisions in the carcass and may even feed them. Yet the larvae can also survive without parental care, using their mandibles to enter the edible nest and feed themselves.

By experimentally manipulating the levels of parental care across 13 generations, Jarrett et al (2018) found that both parental behaviour and offspring anatomy changed. Parents removed before larval hatching began to make the incisions earlier to provide support for the offspring before they hatched. The larvae of such absent parents also evolved larger mandibles to help enter the carcass and feed themselves.

In contrast, when parents were present the larvae had smaller mandibles, as the production of large mandibles is costly and unnecessary when parental support is provided. The research is nice evidence of evolutionary changes to different partners in the parent-offspring dynamic.

Original research: http://dx.doi.org/10.1038/s41467-018-06513-6