Biology Archives - Page 4 of 8

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

October 4, 2018October 4, 2018

Lingering threat

PCB. Lingering threat.

Slinking up food chains, silent.

Killing the killers.

PCBs – polychlorinated biphenyls – were widely used in a variety of manufacturing techniques until they were linked to health problems such as increasing the risk of cancer, disrupting the immune system and impairing reproduction. Despite a ban on their use, the compounds remain an environmental contamination and can accumulate in the tissues of animals, passing up the food chain to accumulate in dangerous levels in apex predators.

Whilst killer whales are one of the most populous mammal species on the planet, research by Desforges et al (2018) suggests that PCB pollution could result in a collapse in over 50% of the world’s killer whale populations. The researchers amalgamated data on PCB concentrations in killer whale tissues from across the world and modelled the predicted impacts of PCB pollution over the next 100 years. The results highlight how important it is to be aware of potential environmental issues, even with species that appear to be thriving.

Original research: http://science.sciencemag.org/content/361/6409/1373

September 18, 2018September 18, 2018

These membrane proteins by Chris Gillen

These membrane proteins

might reclaim salt from urine

or suck it from ponds.

Mosquitoes face extraordinary challenges to their salt and water balance during their complex life-cycles. Larva of most species live in freshwater environments in which they lose salt by diffusion and gain water by osmosis. In contrast, adults live in terrestrial environments where water loss is a problem. Finally, female mosquitoes ingest large amounts of salt and water when they take a blood meal.

In vertebrates, the sodium-potassium-chloride cotransporters (NKCCs) participate in both salt secretion and absorption. Whereas secretory roles for this group of transporters are well-described in insects, their roles in salt absorption are less well studied. Piermarini et al (2017) recently identified yellow fever mosquito transport proteins that have sequence similarity to the vertebrate NKCCs. Two of these transporters apparently resulted from gene duplications early in the insect and mosquito lineages, suggesting that they have diverged into roles related to mosquito osmoregulation. The transporters may contribute to salt absorption, because the researchers found them in adult hindgut and larval anal papillae, both tissues that transport salt into the body.

Original research: Piermarini, P. M., Akuma, D. C., Crow, J. C., Jamil, T. L., Kerkhoff, W. G., Viel, K. C. M. F., and Gillen, C. M. (2017) Differential expression of putative sodium-dependent cation-chloride cotransporters in Aedes aegypti. Comp. Biochem. Physiol. A 214, 40-49. https://doi.org/10.1016/j.cbpa.2017.09.007

Chris Gillen teaches animal physiology and science writing at Kenyon College in Gambier, Ohio. He is author of The Hidden Mechanics of Exercise (Harvard, 2014) and Reading Primary Literature (Pearson, 2007).

September 7, 2018September 7, 2018

No catch-22

Does the protected

lion eat conserved zebra?

Phew! No catch-22!

Recovering predator populations as a result of conservation work can result in impacts on their prey species populations, causing issues if those prey species are themselves endangered. One case in particular is whether lions exert top-down pressure on Grevy’s zebra in Kenya – does the recovery plan of one species negatively affect the conservation of another?

A study by O’Brien et al (2018) suggests we need not worry in this case – working in Laikipia County in Kenya the researchers found that lions were less likely to prey on Grevy’s zebra than expected. In fact, population trends suggest that the Grevy’s zebra population in Kenya may be stabilising. The researchers conclude that the most likely threat to Grevy’s zebra are competition for grass with Plain’s zebra and the impact of livestock.

Original research: http://dx.doi.org/10.1371/journal.pone.0201983

August 31, 2018January 29, 2021

Fluttering by at dusk by Roy McGhie

Fluttering by at dusk,

dawn, and in between.

Crop diversity!

Recent research by Olimpi & Philpott (2018) concludes that crop diversity as a management practice drives bat activity, and that crop diversity and less frequent pesticide use increase bats’ insect prey populations. The study notes that this could be a useful management tool where other options, such as hedgerow or tree management, are not available.

Original research: https://doi.org/10.1016/j.agee.2018.06.008

Roy McGhie works for Natural England as an Uplands Advisor. You can connect with him on LinkedIn here. If you enjoyed his sciku, check out his previous poems Ghost Ponds, A Heady Mixture and Hedgerow Snuffling.

August 17, 2018August 17, 2018

Where are all the wildflowers?

Monoculture crops.

Where are all the wildflowers?

Where is all the life?

Modern intensive agricultural practices have had a devastating impact upon the native wildlife that inhabits arable land, from the density of worms in the soil to the number of apex predators patrolling the skies. In particular, monoculture crops, herbicides, pesticides and the removal of hedgerows have resulted in depleted numbers of invertebrates and subsequently the numbers and variety of birds and other vertebrates that feed upon them.

The farmer and writer John Lewis-Stempel approached this issue by taking a small arable field in south Herefordshire, UK, and spending a year growing wheat following traditional methods. Whilst sowing a mix of wheat he also sowed various species of wildflower, both in the margins of the field and amongst the crop itself. As the year processed he charted the wildlife that appeared in the field, from harvestmen and worms to hares and barn owls.

The blossoming of life was astonishing, absent in the vast, monoculture fields that dominate much of agricultural Britain. Lewis-Stempel’s work begs the question whether such endeavours if repeated across the countryside could transform the levels of biodiversity in the UK? Are the (supposed) gains that modern intensive farming bring worth the environmental devastation they create? As a consumer I am guilty of benefitting from cheap food, it’s hard not to be. But as Lewis-Stempel says “every time one buys the lie of cheap food a flower or a bird dies”. I do believe in flowers and birds, I do, I do.

I can’t recommend his book documenting the project enough: ‘The Running Hare: The Secret Life of Farmland’. From the quality of the prose to the clearly outlined arguments throughout, it is outstanding. If you care about native species, conservation or agriculture then this is essential reading. For everyone else it’s just highly recommended. (And how nice it is to see Herefordshire getting any form of recognition or acknowledgement in the media).

August 14, 2018June 7, 2020

Oh ketchup packet!

How to get the last sauce out?

Hydrocarbon films!

Waste from packaging where food products can’t be completely extracted builds up. Now research by Mukherjee et al (2018) suggests a solution might be at hand. The researchers found that hydrocarbon-based polymer films can be stably impregnated with vegetable oils. The resulting material is slippery and durable, ideal for the inside of packaging to reduce food sticking and waste.

Whilst this sounds high-tech the researchers were actually inspired by the pitcher plant which uses a slippery coating on its leaves to capture visiting insects.

Original research: http://dx.doi.org/10.1038/s41598-018-29823-7

July 17, 2018July 17, 2018

Eggy difference

The Baltic flounder:

Native to namesake region.

Eggy difference.

A new species of flounder has been identified as separate from the European flounder by Momigliano et al (2018). The Baltic flounder (Platichthys solemdali sp.) is native only to the Baltic Sea – the first fish species to be identified as endemic to the area.

Its reproductive behaviour differs from the European flounder, spawning eggs that sink in coastal areas as opposed to buoyant eggs in open water. There are also differences between the species in egg morphology, egg and sperm physiology. Unfortunately, the small morphological differences mean that it is difficult to unambiguously distinguish the species and genetic methods or egg/sperm analyses are required.

Original research: http://dx.doi.org/10.3389/fmars.2018.00225

July 12, 2018July 12, 2018

Extrapolation

from laboratory tests.

Not always correct?

Experiments within the laboratory are often used to understand biological interactions in a controlled manner. Yet research by Comforth et al (2018) suggests that what we learn from the laboratory may not always represent what happens in reality.

The researchers found that Pseudomonas bacteria (a pathogen that threatens immunocompromised people) behaved differently in humans compared to under laboratory conditions. This was particularly apparent in the levels of gene expression involved in antibiotic resistance, cell to cell communication and metabolism. The implications of this work suggest laboratory studies only take us so far and further understanding bacterial behaviour in humans is just as important.

Original research: https://doi.org/10.1073/pnas.1717525115

July 6, 2018July 6, 2018

Snakeskin secrets

Learning from nature:

Snakeskin secrets revealing

lessons in friction.

The natural world has inspired engineering and design in countless ways. Now researchers are looking at snakeskins in an attempt to better understand an understudied engineering area: friction.

Abdel-Aal (2018) summarises findings from 40 species of snake to understand how the textural traits of snake skin compare to the standard features of textured industrial surfaces. This exploratory framework could subsequently lead to new, nature-inspired smart surfaces.

Original paper: https://doi.org/10.1016/j.jmbbm.2017.11.008

July 3, 2018July 12, 2018

Chestnut menace

Invading clonal

wasps. Chestnut menace spreading

yet no males required.

The Chestnut gall wasp arrived in Europe in 2006, imported accidentally from China. Since then it has begun to spread and devastate European Chestnut trees.

Bonal et al (2018) have now revealed that the European population has very low genetic diversity due to 1) the founding of the population by a small number of individuals, 2) an endosymbiont bacterial infection present within the population that is known to have male-killing tendencies and 3) it’s parthenogenetic reproduction strategy. This is where females are able to reproduce and produce female offspring without the need to be fertilised by males. No males have been observed in the European population and the females and their offspring are effectively clones of one another.

Original research: https://doi.org/10.1038/s41598-018-23754-z

June 8, 2018June 7, 2020

Forgotten value

of seagrass meadows. Crucial

for world’s fisheries.

Life in the ocean is under threat from a variety of manmade issues, including climate change, mining and over-fishing. Yet our understanding of marine ecosystems still remains far from complete.

New research by Unsworth et al (2018) has revealed just how important seagrass meadows are for fish populations and as a result for humanity’s fisheries. Seagrass meadows are found in the shallow seas around all the continents (aside from Antarctica) between the intertidal zone and 60 meters deep.

The researchers found that seagrass meadows provide a nursery habitat for over a fifth of the world’s largest 25 fisheries and provide support to a large number of other small-scale fisheries around the world. The study indicates that these seagrass meadows should be maintained in order to maximise their role in global fisheries production.

Original research: https://doi.org/10.1111/conl.12566

Interested in seagrass meadows? They also play a hugely important role in sequestering carbon. Find out more with this sciku here.

June 6, 2018June 6, 2018

Giant becomes five

endangered salamanders.

Hidden extinction?

The Chinese Giant salamander is the world’s largest amphibian, adults can be 2 meters long and weigh up to 50 kg. It’s critically endangered in the wild due to habitat destruction, fungal infection and because the species is used as a luxury food source in China. It is kept in far greater numbers in captivity as a result of it being farmed for food. Two studies published in Current Biology add additional concerns for the future of this species in the wild.

In what is thought to be the largest wildlife survey conducted in China, Turvey et al (2018) found that giant salamander populations were either critically depleted or had been eradicated, as well as finding plenty of evidence for illegal poaching. The researchers were unable to confirm the survival of wild Chinese giant salamanders at any of their survey sites, raising the question of whether this species is all but extinct in the wild.

In a companion piece of research, Yan et al (2018) performed a genetic analysis on Chinese giant salamanders and found that the species actually consists of at least five species-level lineages, potentially up to eight. This suggests that some of these distinct lineages (effectively separate species) may well have already gone extinct in the wild – a phenomenon known as cryptic or hidden extinction. This has crucial importance for conservation efforts, particularly with regards to re-releases from captive populations where the five lineages have been mixed and the resulting offspring are effectively hybrids.

Original research:

Turvey et al (2018): https://doi.org/10.1016/j.cub.2018.04.005

Yan et al (2018): https://doi.org/10.1016/j.cub.2018.04.004

May 25, 2018May 25, 2018

The year’s best species

Mystery protist.

Apes, snailfish and amphipods.

The year’s best species.

Every year since 2008 the College of Environmental Science and Forestry has released a Top 10 New Species list. 2018’s selection include single celled organisms, plants and animals (including two species of beetle) as well as a prehistoric marsupial lion identified from fossils. All 10 species are fascinating but those highlighted in the sciku are:

Protist – Ancoracysta twista, a single celled predatory Eukaryote with harpoon-like organelles that it uses to immobilise its prey. Intriguingly its evolutionary origins are unclear and it doesn’t fit neatly within any known groups.

Ape – Orangutans now come in three flavours: Bornean, Sumatran and now a newly identified Southern Sumatran species of orangutans. It is the most endangered great ape in the world.

Snailfish – Whilst snailfish are found at all depths, 2018’s species is the deepest fish in the sea, found in the Mariana Trench at 7,966 meters below the surface. It appears to be the top predator in its benthic community and is tadpole-like and around 4 inches long.

Amphipod – Epimeria quasimodo is found in the Antarctic Ocean. The 2 inch long crustacean takes its name from the hunchback of Notre Dame and has beautiful vivid colours.

May 17, 2018May 17, 2018

You aren’t one of us.

Help! Help! Predator!

Guys, why aren’t you helping me?

You aren’t one of us.

Jackdaws respond to anti-predator calls to join the caller in mobbing the predator and driving it away. Yet researchers have now found that who the caller is will affect the level of response.

In playback experiments Woods et al (2018) that the highest response was to nestbox residents who would be highly familiar with the caller. The level of response to an anti-predator call diminished as familiarity decreased from colony members to non-colony members and then to rooks (a species that often lives alongside jackdaws).

Original research: http://dx.doi.org/10.1038/s41598-018-25793-y

May 11, 2018May 14, 2021

TF gets in on the bud by Jolene Ramsey

Fat tags the protein

To the surface it transits

Wrapped in the virus

Living cells are like microscopic cities. The proteins, which are the workhorses of a cell, must accurately navigate to the place where they will perform their assigned tasks. Sometimes we equate the way that proteins get to their final destination to adding an address to a letter.

When a virus infects a cell, its proteins must conform to the cell norm or rewire the system. It is of interest to understand how viruses approach this problem. In the case of a small accessory protein called TF that is found in the virions of Sindbis virus, adding lipids to the protein serves as its ‘address’ to get it to the location where new virions are released from an infected cell.

Original research: https://dx.doi.org/10.1128%2FJVI.02000-16

During graduate school, Jolene Ramsey studied the molecular mechanisms governing enveloped eukaryotic virus assembly. She has a long-term interest in understanding how viruses exploit host cells to build more virions. You can follow her on Twitter under the handle @jrrmicro

Enjoyed Jolene’s sciku? Check out her other sciku ‘Click click go!’, ‘Privateer, the phage’, ‘The Phriendly Phage’ and Saba, the morning breeze.

April 17, 2018April 20, 2018

Cuckoo bee

No longer extinct,

cuckoo bee, nest parasite,

found further afield.

The Macropis Cuckoo Bee was thought to be extinct until the early 2000s when a specimen was found in Nova Scotia. The bee is one of the rarest bees in North America, with only a handful found during the past decades. A new specimen found in Alberta and reported by Sheffield and Heron (2018) has now pushed the known geographical range of the Macropis Cuckoo Bee further west and gives hope to the continued survival of this species.

The Macropis Cuckoo Bee lays its eggs in the nests of Macropis bees and therefore requires the presence of its hosts in order to reproduce, yet cuckoo bees are not always found where their hosts are. In turn Macropis bees are entirely dependent on plants of the primrose genus meaning that the there is a chain of co-dependence between the plants, bees and cuckoo bees.

Original research: http://dx.doi.org/10.3897/BDJ.6.e22837

April 17, 2018May 20, 2021

Have frog, will travel

Have frog, will travel,

yet what impact on welfare?

Best to avoid moss.

Transporting animals for research, agricultural, conservation or leisure reasons can involve a range of potential stressors. It’s therefore important to be aware of the impact of transportation on animals so as to minimise any negative effects.

African clawed frogs are a common laboratory animal, used for a range of developmental studies. Holmes et al (2018) investigated the impact of transportation between research facilities. They found that transportation and re-housing had a negative impact across a short- and longer-term, with corticosterone (a ‘stress hormone’) remaining high for 1 week and body mass remaining low for 5 weeks after transportation. Investigating further the researchers found evidence that being transported in moss might be the least preferable transport medium, with water or sponge appearing to be more suitable.

Original research: https://doi.org/10.1016/j.ygcen.2018.03.015

Interested in African clawed frogs? Check out these other Xenopus sciku: ‘Clawed frogs indicate‘, ‘Xenopus enrichment‘, ‘Fungal culprit‘ and ‘Reservoir or predator‘.