Biology Archives - Page 6 of 7

October 30, 2017October 30, 2017

Declining monarchs

Declining monarchs:

Habitat not climate is

your Achilles’ heel.

Understanding why a species is declining is a large part of establishing a suitable conservation approach. In North America the monarch butterfly population has sharply declined in recent decades, yet the reasons for this were unclear until now.

Thogmartin et al (2017) investigated monarch butterfly populations and found that the decline is largely down to habitat loss from herbicide use and the loss of overwinter forest, as well as insecticides. Whilst climate impacts on yearly population size, this is not enough to explain the decreases in monarch butterfly population recorded over recent decades.

Original Research : https://doi.org/10.1098/rsos.170760

October 23, 2017October 23, 2017

Arachnid genome

duplicated long-ago.

Arachnid genome.

Sometimes having two of something is a good thing. Genes are occasionally duplicated and whilst duplications are often lost, they may be retained and may help aid the evolutionary diversification of organisms. Normally only a few genes are duplicated but occasionally duplication can occur on a greater scale.

Schwager et al (2017) sequenced the genome of the common house spider and found evidence that whole genome duplication occurred in the house spider’s distant past. In fact, comparison with the genome of bark scorpions suggests that the duplication event took place in the common ancestor of spiders and scorpions more than 450 million years ago.

Original research: https://doi.org/10.1186/s12915-017-0399-x

October 16, 2017August 9, 2019

Flocks of new markers

Little white sponges,

filtering in mining zones:

Flocks of new markers.

New species are being discovered all the time and even the most innocuous can be important. A new species of sponge has been discovered and recorded by Lim et al (2017) at a depth of 4000m on the abyssal seafloor of the central Pacific Ocean. Morphologic and genetic analysis of the sponges (Plenaster craigi) has revealed they are a new genus, currently placed within the family Stelligeridae.

The region where the sponges are found is rich in polymetallic (metal-rich) nodules and may well be subjected to deep-sea mining. The sponges could be useful indicators of the impacts of such mining efforts – they are abundant on the nodules, are easily identified and are filter-feeders so sensitive to changing conditions.

The Latin name Plenaster is due to the abundance of star-shaped microscleres within their bodies, whilst the species name of craigi is in honour of the Chief Scientist on the expeditions that sampled the species Professor Craig R. Smith of the University of Hawaii.

Original research: http://dx.doi.org/10.1080/14772000.2017.1358218

October 13, 2017October 13, 2017

Tool of the future?

Environmental

DNA: Conservation

tool of the future?

Conservation efforts depend on the knowledge of species distribution patterns and population size estimates in order to know what needs protection and the subsequent impacts of conservation efforts. But there are a number of difficulties association with biodiversity monitoring techniques, including issues to do with correct species identification and invasive methods.

Environmental DNA – “genetic material obtained directly from environmental samples (soil, sediment, water etc.) without any obvious signs of biological source material” – could be a non-invasive and easy to standardise method of biodiversity monitoring. The advances of next-generation sampling technologies has meant individual or multiple species (through DNA metabarcoding) can be detected from such environmental samples quickly and cheaply.

Thomsen and Willerslev (2015) provide a thorough review of the main findings, future potential and limitations of eDNA for biodiversity monitoring and conservation. They document the successes of eDNA so far and discuss pitfalls such as contamination, inhibition, errors, interpretation and problematic reference DNA databases.

October 9, 2017October 9, 2017

Black and white cat-foot

Black and white cat-foot.

Your numbers are rising but

your home shrinks and splits.

The giant panda (whose Latin binomial name literally means black and white cat-foot) is a poster species for animal conservation yet recently the IUCN Red List downgraded the species from endangered to vulnerable based on an increase in adult population since 1988.

Despite this population increase there remains concern for the future of the species. A study by Xu et al (2017) using remote sensing data suggests that both the total amount of available giant panda habitat and the average size of habitat patches (an indication of habitat fragmentation) have decreased substantially. Whilst total area and habitat patch size have shown signs of an recovery since 2001, they still remain below 1988 levels (1.7% and 13.3% lower respectively).

October 6, 2017October 6, 2017

Secretive flatworms

divide coyly in darkness

by three-stage fission.

Freshwater flatworms are able to reproduce asexually by dividing in half – the head and tail pieces then each become a new worm. This process of binary fission was previously difficult to study as it occurred in darkness, halts with any disturbance and occurs infrequently (about once a month) but researchers now have more of an understanding of how the process occurs.

Malinowski et al (2017) found that fission occurs in three steps: 1) a local constriction along the body of the flatworm as if a waist is forming, 2) pulsations that apply stress to the ‘waist’ ultimately leading to 3) a rupture at the waist and the creation of two pieces which then re-grow their missing halves. The researchers also developed a linear mechanical model of the fission enabling a better understanding of the division process and accurate predictions of where on the body of a flatworm it will occur.

October 2, 2017October 2, 2017

Their noses know

How do shearwaters

navigate across oceans?

Their noses know ¿no?

Many birds travel hundreds of miles across oceans with no obvious sign posts to help them find their way. So how do they navigate?

Padget et al (2017) manipulated the olfactory ability of shearwaters and then tracked them as they made free-ranging foraging trips across the Mediterranean Sea. Shearwaters that were anosmic behaved as normal whilst foraging but on their return trips they were not oriented towards their colony – they found the coastline within 40 km from their colony and travelled the rest of the way along the coast. In contrast the control birds found their colony with a significantly greater degree of accuracy. This suggests that shearwaters use an olfactory map to navigate across open water successfully.

September 29, 2017September 29, 2017

Cause and effect

They’ll blow your house down

as they grasp cause and effect

much better than dogs.

The process of domestication is thought to impact on a number of cognitive and physical properties as species adapt to the human environment. The close social ties between humans and dogs are an extreme example and comparing the cognition of dogs with wolves can reveal information about the impact of domestication.

Using animals housed under similar pack conditions and with prior experience of interacting with humans, Lampe et al (2017) found that whilst wolves and dogs can follow human-given communication equally well, wolves were better at understanding causal cues in the absence of humans (such as a rattling container indicating the presence of food). Domestication may have led to a reduction in the ability of dogs to solve some problems independently of humans.

September 25, 2017September 25, 2017

The climate matters

when measuring hormones from

faeces – be careful!

Measuring changes in hormones can tell us a lot about an animal’s welfare, health and reproductive condition, and non-invasive sampling (for example using faecal matter instead of blood) can limit the amount of stress caused to the animal being monitored. But faecal samples that are collected on an opportunistic basis might not be fresh or may have been exposed to the elements prior to collection. Does this matter?

Research by Yarnell & Walker (2017) suggests that temperature does indeed have an effect on the results obtained, with exposure to room temperature and high heat showing an increase in faecal glucocorticoid metabolite levels over time. This fundamental work shows the importance of considering sample collection and storage whilst designing experiments.

September 22, 2017December 11, 2017

Do creepy-crawlies suffer?

Do creepy-crawlies

suffer as live food? Is this

a welfare concern?

Invertebrates are often used as live food for other animals in captivity (for example geckos are often fed live crickets). Increasingly there are suggestions that some invertebrate species may be able to experience a sensation of pain and may have higher cognitive functions such as emotions and learning. As a result, should we be considering the ethical and welfare issues associated with using invertebrates as live prey?

Keller (2017) has published a review of the latest research into invertebrates and how institutes using live prey might consider and act on any welfare implications. Since there is mounting evidence that some invertebrate species can suffer, perhaps it would be best to stop all live prey feeding? But this response has its own problems: live prey feeding provides enrichment to captive species and many captive species will not feed if the food item is dead.

September 18, 2017September 18, 2017

Alchemist goldfish

change acid to alcohol

through doubled proteins.

Many species of carp (including goldfish) can survive for months over winter in frozen lakes despite a lack of oxygen. Without oxygen they use anaerobic respiration resulting in the production of lactic acid. To avoid a deadly build up of lactic acid the fish convert it into ethanol which diffuses across their gills into the surrounding water.

Researchers have now discovered how the fish do this. During energy production in the absence of oxygen a mutated set of proteins switches the metabolic pathway within mitochondria to produce ethanol instead. The fish have two sets of these proteins, one set which is very similar to that found in other species and one set that appears to be a duplicate of the first. These sets of proteins appear to have arisen during a whole genome duplication event approximately 8 million years ago and have enabled the fish to survive in conditions other species can’t. Fagernes et al, 2017.

September 15, 2017September 15, 2017

The kids help out

Staying at home, the

kids help out. Breeding becomes

cooperative.

In cooperatively breeding species individuals help to raise offspring that are not their own, but how did this costly behaviour evolve? By comparing 3,005 species using phylogenetic analyses Griesser et al (2017) suggest that cooperative breeding in birds occurred in two stages.

First, families formed by the prolonging of parent-offspring associations, with chicks not leaving the nest when nutritionally independent. This appears to have occurred in productive environments where the cost of the offspring remaining at home for longer is less.

Second, the offspring remaining at the home nest then start to help out. In contrast to the formation of family units, the researchers suggest that this happened in more variable environments where the retained helpers can buffer in harsh years.

This theory helps to explain the geographic distribution of cooperatively breeding bird species too – areas where these species are found have often experienced historical declines in productivity. The pre-decline environment may have fostered family formation whilst the decline may have then resulted in the step to cooperative breeding.

September 11, 2017September 11, 2017

Lurking inside intestines

The fountain of youth

lurking inside intestines:

Microbiota.

Gut microbes are important for digestion, nutrition and immunity, and gut microflora may impact on life expectancy. Young African turquoise killifish have diverse microbial communities but this diversity decreases over time. By feeding middle-aged killifish the microbes from younger fish, Smith et al (2017) found that the older fish lived longer and were more active in later life. Manipulating gut microbe composition may therefore be a way of delaying diseases related to ageing.

September 8, 2017September 8, 2017

Ancestral origami

To fold life’s proteins:

Ancestral origami

around hockey pucks.

The basic way DNA is stored within cells is remarkably conserved suggesting a deep ancestral origin. Mattiroli et al (2017) have revealed that the way DNA is folded in eukaryotes (a domain containing animals, plants, fungi and protists) is very similar to the way its folded in archaea, a domain of single-celled microorganisms containing some of the oldest forms of life.

In both eukaryotes and archaea DNA is wrapped around proteins called histones creating the same DNA geometry. This suggests that eukaryote DNA folding method is ancestral, although a key difference is that in eukaryotes DNA is wrapped around bundles of 8 histones (sometimes referred to as a ‘hockey puck’) whilst in archaea its just wrapped around individual histones.

September 4, 2017September 4, 2017

Is ‘P’ suitable?

Refine and reduce

for animal welfare, but

is ‘P’ suitable?

Statistics and animal welfare might seem like unlikely bedfellows but a greater understanding of statistics may actually improve animal welfare. The 3Rs – Replacement, Reduction and Refinement – are critical for the ethical use of animals in experiments, but sometimes the animal species concerned cannot be replaced with a more ethical substitute. Refining procedures and reducing the numbers of animals tested should therefore be a fundamental consideration of any animal experiment.

Determining an appropriate sample size is often done using power analyses based around the P-value, but increasingly there is concern about the validity of this statistical term as a means of accepting or rejecting the experimental hypothesis. Instead, effect sizes and confidence intervals could be used to determine an experiment’s outcome and, in turn, minimum suitable sample size could be calculated using effect size precision. In this way statistics can be used to improve animal welfare by reducing the numbers of animals used. Sneddon et al, 2017.

September 1, 2017September 1, 2017

Just nicker!

Don’t make yourself hoarse

in anticipation of

good times, just nicker!

Vocal communication is an important element of behavioural interactions within many social species. Przewalski’s horses produced more whinnies and squeals in response to negative contexts (agonistic interaction, social separation), but more nickers in positive contexts (anticipation of food or affiliative interactions).

Przewalski’s horses are the closest living relative of domestic horses and a comparison between the species revealed both similarities and intriguing differences in their vocalisations, suggesting that the expression of emotional valence (positive or negative) might be species specific as opposed to conserved across species. Maigrot et al, 2017.

Being able to understand vocal expression of animals could lead to the increased welfare of captive species and a better understanding of animal interactions and group behaviour, which in turn might help to aid population management or conservation in endangered species.

August 30, 2017August 30, 2017

Pray, are you a predator?

Have we met before?

Pray, are you a predator?

I am so naive!

Predators are a threat for most animals and gauging whether a novel species is dangerous or not can be a life or death judgment. Whilst some species may have a degree of innate predator recognition, research suggests other species require prior experience of the predator to learn of its danger.

Great and blue tits were tested with novel and familiar predators. Tits from populations familiar with both sparrowhawks and little owls reacted towards the stimuli as expected, mobbing the predators equally. But tits from populations only familiar with sparrowhawks did not treat the little owl stimulus as a threat, suggesting it wasn’t recognised as a predator. Prior experience of predator species is therefore important in great and blue tits. Carlson et al, 2017.

August 25, 2017August 25, 2017

Hijacked ant

Little hijacked ant,

blade held in jagged pincers,

awaits her demise.

The lancet liver fluke is a parasite of devious means. As an adult it lives in the livers of ruminant animals, often cattle, but it has an ingenious method of getting from one liver to another. First, its eggs are excreted in its host’s faeces, which is then consumed by a snail. The larvae develop into juveniles in the snail’s digestive tract and are eventually themselves excreted.

This is where the ants come in. Ants use snail slime for moisture and so consume the juveniles. Once inside an ant the parasites cause it to climb a blade of grass and clamp its mandibles to the top. The ant will remain attached all night and then return to its normal behaviour during the day. The aim of the parasite is for the ant (and attached blade of grass) to be eaten by a grazing animal – the parasite is then back in its main host and the cycle starts again. Summarised in Tarry, 1969.

August 23, 2017May 20, 2021

Fungal culprit

Fungal culprit of

amphibian genocide –

Innocent scapegoat?

Amphibian populations are in the midst of a pandemic, the spread of chytrid fungus devastating species around the world. Conservationists have pointed a finger of blame at African clawed frogs: they are hosts of the fungus, have a degree of immunity and have spread around the world due to their use in research laboratories and hospitals.

The circumstantial evidence seems damming but research by Tinsley et al (2015) into long-standing UK populations suggests otherwise. Native amphibian species present alongside populations of African clawed frogs were not infected with chytrid fungus, despite the African clawed frogs themselves carrying it. What’s more, the African clawed frog populations have been present for decades yet surveys revealed continued high native species abundance. If fungal transmission from African clawed frogs were an issue then such levels of native amphibians would be unlikely.

It seems then that African clawed frogs may be scapegoats after all.

Interested in African clawed frogs? Check out these other Xenopus sciku: ‘Clawed frogs indicate‘, ‘Have frog, will travel‘, ‘Xenopus enrichment‘ and ‘Reservoir or predator‘.

August 21, 2017August 21, 2017

Frozen anoles

must evolve cold tolerance…

and flipping quickly!

Evolutionary changes can occur quicker than you might think. A severe cold snap in the winter of 2013-2014 led green anole lizards to develop an increased cold tolerance as measured by a loss of coordination when flipped over. Further investigation of the populations revealed changes at six genomic regions that are known to be important for regulation of function in the cold. Campbell-Staton et al, 2017.

Interested in rapid lizard evolution? Try this sciku by Roy McGhie: A Heady Mixture.

August 18, 2017January 29, 2021

Ghost ponds by Roy McGhie

After many moons,

even when buried alive –

Zombies in ghost ponds!

A study in Norfolk has shown that historic ponds infilled by agricultural activity, even after over 100 years have passed, maintain viable aquatic plant propagules. These ghost ponds can have the potential to restore locally extinct species assemblages. Alderton et al, 2017.

Roy McGhie works for the North Yorkshire Moors National Park as a Countryside Manager. He has a strong background in environmental conservation and education, and plays a mean game of tennis. You can connect with him on LinkedIn here. If you enjoyed his sciku, check out his other poems A Heady Mixture, Fluttering By At Dusk and Hedgerow Snuffling.

August 16, 2017August 30, 2017

Can herbivores relax?

My how big you are!

and yet your range contracts. Can

herbivores relax?

As the human population around the world expands, the impact we have on wildlife increases due in part to more land being used for habitation or agricultural purposes. Large carnivores are particularly vulnerable to anthropogenic threats such as loss of prey base and human-wildlife conflict (often to do with livestock).

Wolf & Ripple (2017) created and analysed large carnivore range maps from present and historical (~AD1500) data. They found that large predators historically occupied 96% of the world’s land area whereas now they occupy 34%. A number of species have suffered an decline in range of over 90%, including the red wolf (99.7%), Ethiopian wolf (99.3%) and the tiger (95.3%). Overall the greatest range contractions occurred in South-eastern Asia and Africa.

August 14, 2017September 8, 2017

Twisted naval string

Twisted naval string:

Forty turns of jelly and

contrary vessels.

Break benefits both before

severing the thread of life.

The umbilical cord has traditionally been cut (or at least clamped) 15-20 seconds after birth but increasingly research suggests that a longer delay before cutting is beneficial for both term and pre-term infants.

For term infants a delay of 30-60 seconds can increase haemoglobin levels at birth and iron stores in the first months of life. In preterm infants a delay can improve transitional circulation, result in the better establishment of red blood cell volume and decrease the need for blood transfusions.

A delay before clamping and cutting is therefore recommended by both the World Health Organisation and the American College of Obstetricians and Gynaecologists.

This sciku is actually an example of a tanka – the first two verses of a traditional renga, where haiku originate from. Learn more about haiku, renga and tanka here.

August 11, 2017January 29, 2021

A heady mixture by Roy McGhie

Sun-basking lizards

plus man-made evolution –

A heady mixture.

Evolution doesn’t always have to take place over long periods of time. Recent research has shown that some lizards on Brazilian man-made islands have developed larger heads than their mainland counterparts in only 15 years. Eloy de Amorim et al, 2017.

Roy McGhie works for the North Yorkshire Moors National Park as a Countryside Manager. He has a strong background in environmental conservation and education, and plays a mean game of tennis. You can connect with him on LinkedIn here. If you enjoyed his sciku, check out his other poems Ghost Ponds, Fluttering By At Dusk and Hedgerow Snuffling.

August 9, 2017August 9, 2017

Gamma sabres by Hannah Hall

Gamma sabres slay

Alzheimer’s amyloid plaques

with disco lighting.

Alzheimer’s disease is a neurodegenerative condition that worsens over time leading to problems with short-term memory, mood swings, behavioural issues and ultimately loss of bodily functions and death. But could flashing LED lights be a method of helping to treat the disease?

Exposing laboratory mice to LED strips flickering at 40Hz for an hour reduced beta amyloid plaque levels in the visual cortex by half, reduced Tau protein abnormalities and enhanced gamma oscillations (brain waves) – all of which are characteristics of Alzheimer’s disease. Iaccarino et al, 2016.

Hannah Hall is a Senior Consultant at Pragma Consulting Ltd in London. Though she studied Russian and French at university, she has broad interests and enjoys listening to the RadioLab podcast where she heard about this research.

August 7, 2017August 30, 2017

Orienteering

Oh little spined fish,

your habitat matters for

orienteering.

Animals navigating their environment may use a number of different spatial cues to find their way around, including the geometric structure of the environment or global landmarks. But some species are found in multiple habitat types where different cues might be more effective for navigation.

Three-spined sticklebacks live in rivers and ponds, environments which differ in terms of structure and rate of environmental change. When tested in an aquatic maze, sticklebacks collected from rivers used geometric and global cues to learn the maze, whereas sticklebacks collected from ponds only used geometric cues to navigate the maze. Within this one species of fish there appear to be multiple methods of navigation depending on the habitat in which the fish are found. Brydges et al, 2008.

July 27, 2017July 27, 2017

Bumblebees bumble

Towards one third extinction

One bee, Two bee, Oh!

There are 260 known species of bumblebees globally many of which are important pollinators, particularly in agriculture. A phylogenetic study of ~43% of these species has revealed that approximately one third of the species are declining. The Thoracobombus subgenus which accounts for 64% of species tested is particularly vulnerable, as are species of bumblebee with small geographic ranges. Arbetman et al, 2017.

Interested in bumblebees? Check out this sciku on bumblebee cognition: Bumblebee football.

July 25, 2017August 30, 2017

Tiny passengers

What will satisfy

these cravings? I should ask my

tiny passengers.

Choosing what and how much to eat is crucial as even those nutrients that are normally beneficial can be harmful if consumed excessively. But the mechanism for how animals regulate the amount they eat isn’t always clear.

The common fruit fly develops a strong appetite for amino acid-rich food if fed a diet lacking in certain essential amino acids, and the fly’s reproductive effort will also decrease. However, this change in appetite and reproduction is suppressed if the fly has certain species of gut bacteria. Interestingly, when given the choice fruit flies will eat more food that contains these bacteria than food that doesn’t suggesting an ability of the flies to direct their own gut bacterial microbiome.

How the bacteria influence fruit fly behaviour and physiology is uncertain but results suggest that it is not down to the bacteria producing the missing amino acids for the flies or that the flies are consuming the bacteria themselves. Possible explanations are that the bacteria secrete metabolites that help the flies use their remaining amino acids more effectively or that the bacteria directly modulate the flies own nutrient sensing pathways so that the flies don’t recognise a decrease in amino acids. Leitão-Gonçalves et al, 2017.

July 21, 2017May 20, 2021

Clawed frogs indicate

by action and reaction

a choice between shades.

Ensuring the welfare of animals used for research is vital both from an ethical stand point and for the quality of the research produced – animals in poor condition do not produce accurate or reliable results. The African clawed frog is a common research species found in laboratories around the world but little work has investigated how to optimally house it in captivity.

Holmes et al (2016) found that a black tank background produced lower levels of ‘stress’ hormone (corticosterone), lower amounts of stereotypical behaviour and a smaller loss in body mass than a white tank background.

As African clawed frogs are naturally dark green/brown in colour and use camouflage to avoid predation, a light background might be more stressful for the frogs as they may appear more exposed. Providing dark tank backgrounds could therefore be an easy method for improving the welfare of thousands of African clawed frogs housed in captivity around the world.

Interested in African clawed frogs? Check out these other Xenopus sciku: ‘Fungal culprit‘, ‘Have frog, will travel‘, ‘Xenopus enrichment‘ and ‘Reservoir or predator‘.