Biology Archives - Page 6 of 9

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‘.

April 3, 2018April 27, 2018

How you handle mice

affects response to rewards.

Science improves too!

There is an increasing body of research to suggest that handling laboratory mice by the tail is both bad for their welfare and the science that the mice are studied for. Tail handling has negative impacts on mouse behaviour and physiology, with tunnel and cupping handling techniques resulting in behavioural improvements across various common behavioural bioassays, including the elevated plus maze, the open field test and the habituation-dishabituation paradigm.

Now new research suggests that handling is also important for reward-based behavioural assays. A study by Clarkson et al (2018) examined mouse response to sucrose solution (a common reward). They found that tail handled mice showed a reduced response to the sucrose than the tunnel handling method, a finding indicative of the tail handled mice having a ‘decreased responsiveness to reward and potentially a more depressive-like state’.

Across eight years and five research papers, from three distinct research groups in two countries, the field of laboratory mouse research has been irrevocably changed. Combined, the research suggests that tail handling results in poor animal welfare and potentially erroneous scientific results. The National Centre for the Replacement, Refinement & Reduction of Animals in Research now has extensive information on mouse handling techniques, example videos, tips and testimonials for researchers and animal carers to find out more about changing their current mouse handling methods to the tunnel or cupping techniques.

Original research: http://dx.doi.org/10.1038/s41598-018-20716-3

April 3, 2018April 30, 2018

Tunnels and cupping

beat tail handling mice for

behavioural tests.

Laboratory mouse handling method can affect mouse behaviour and physiology, and new research suggests that it can also impinge on mouse performance in behavioural tests. Research by Gouveia and Hurst (2017) found that tail handled mice performed poorly in a habituation-dishabituation paradigm test in comparison to cupped or tunnel handled mice. The tail handled mice ‘showed little willingness to explore and investigate test stimuli’ and even prior familiarisation with the test arena didn’t improve their performance much.

Combined with the previous research findings on mouse handling this research continues to expand on the long-reaching impacts of mouse handling technique on both mouse welfare and scientific experimental rigour and asks the question – just how valid are behavioural tests using laboratory mice that have been tail handled? Yet the story of mouse handling is not yet done, click here for the final instalment of this tale/tail!

Original research: http://dx.doi.org/10.1038/srep44999

April 3, 2018April 30, 2018

Cup handled mice

Cup handled mice show

improved glucose tolerance

and less anxiousness.

When performing scientific research with animals, it’s important to ensure that the procedures used do not themselves impact upon the results obtained. Laboratory mouse handling method has already been shown to impact upon mouse anxiety in common behavioural tests. However it seems that handling can have physiological impacts too.

Ghosal et al (2015) compared the behavioural and physiological responses of laboratory mice to either tail handling or cupped handling techniques. Cupped handled mice showed fewer anxious behaviours in a common behavioural test, reduced blood glucose levels and a lower stress-induced plasma corticosterone concentration in response to an overnight fast compared to tail handled mice. The researchers also found that obese laboratory mice handled using the cupped method demonstrated improved glucose tolerance.

Replication and repeatability are crucial components of science and this paper is a perfect demonstration of this – the researchers are from different research laboratories and in a different country to the mouse handling work that preceded it. In this way not only does it build on what came before, it also strengthens those earlier findings. Yet the mouse handling story is not finished yet, click here for the next chapter of this tale/tail!

Original research: https://doi.org/10.1016/j.physbeh.2015.06.021

April 3, 2018April 30, 2018

Reducing mouse anxiety

Further reducing

mouse anxiety using

familiar tunnels.

Building on the finding that handling laboratory mice using a tunnel resulted in lower anxiety than picking them up by the tail, Gouveia and Hurst (2013) next investigated whether familiarity with the tunnel might be an important factor. Once again they found that tunnel handling resulted in lower anxiety than tail handling during an elevated plus maze (a common behavioural test for laboratory mice).

This time they found differences between mouse strains, with C57BL/6 mice being most interactive towards tunnels from their home cage and ICR mice showing no difference in interaction between familiar home cage tunnels and novel tunnels previously used for handling mice from other cages. The researchers suggest that ‘as home cage tunnels can further improve response to handling in some mice, we recommend that mice are handled with a tunnel provided in their home cage where possible as a simple, practical method to minimise handling stress’. The tunnel would also act as a form of environmental enrichment for the home cage.

In science it’s rare to tell a complete story through the findings of two research papers, click here for the next chapter of this tale/tail!

Original research: https://doi.org/10.1371/journal.pone.0066401

April 3, 2018April 30, 2018

The little changes

can make a big difference:

Handle mice with care.

Traditionally laboratory mice are handled by picking them up by the tail, yet increasing evidence suggests that this is bad, both for the mice themselves and the quality of the science they are being used for. The evidence for this started building from Hurst and West’s 2010 study which demonstrated that handling by the tail resulted in increased aversion and anxiety.

The researchers proposed two alternative methods for handling laboratory mice: holding the mice cupped in the hands or using tunnels that the mice can crawl into and be transported by carrying the tunnels. These novel methods of handling led to the mice approaching the handler voluntarily, being more accepting of physical restraint and showing lower levels of anxiety.

In science it’s rare to tell a complete story through the findings of a single research paper, click here for the next chapter of this tale/tail!

Original research: http://dx.doi.org/10.1038/nmeth.1500

April 3, 2018April 12, 2018

Letter from Ternate by Prof Donald M Waller

Thinking to respond

Darwin despaired, paused, then shared.

Pressed to Origin.

Charles Darwin first conceived of his theory of evolution by natural selection in the late 1830s and began work in earnest on his “big book” in the 1840s. Yet it was not until he received a letter from Ternate, Indonesia, from the younger naturalist Alfred Russell Wallace in 1858, threatening to rob him of his originality for the idea, that he was pressed into months of intense activity to publish in 1859 an “abstract” of his longer work that appeared as “On the Origin of Species by Means of Natural Selection . . ”

Darwin was thrown into great anguish by Wallace’s letter and request from Wallace to help get it published. He confided in scientist friends who urged him to prepare a parallel brief summary of his own ideas, extracted from his private essay of 1842. They arranged for both papers to be read before the Royal Society. These did not attract much interest, but “On the Origin” certainly did.

Knuckle cracking maths

Knuckle cracking maths:

Synovial bubbles pop

in partial collapse.

The debate over how knuckles cause a popping sound when cracked has lasted for decades. Now, Chandran Suja and Barakat (2018) have created three equations to mathematically model how the sound is produced. The first equation describes variations in pressure inside the joint, the second describes how pressure variations results in bubble size variations, whilst the third equation links the size variation of bubbles with the production of acoustic pressure waves.

When cracking your fingers the joints are pulled apart, the pressure goes down and bubbles appear in the synovial fluid which lubricates the joint. During knuckle cracking the pressure changes within the joint causing the size of the bubbles to fluctuate quickly resulting in the popping sound. The new model reveals that the bubbles don’t need to completely collapse in order to produce the sound, explaining why bubbles are observed following knuckle cracking.

Original research: http://dx.doi.org/10.1038/s41598-018-22664-4

April 3, 2018April 3, 2018

Patches on Venus

Patches on Venus:

Atmosphere harbouring the

conditions for life?

In the hunt for extra-terrestrial life, Venus is rarely considered due to the high surface temperatures (~465 °C) and the intense atmospheric pressure (92 times that on Earth). Yet a new study by Limaye et al (2018) suggests that life off the surface of the planet may be possible since the lower cloud layer harbours conditions suitable for microbial life: water, solutes, ~60 °C and an atmospheric pressure roughly equivalent to Earth.

What’s more, observations of Venus have revealed dark patches in the atmosphere that change shape, size and position over time. These are made up of particles roughly the same size as common Earth bacteria and also absorb light of at a similar spectrum. The changes in patch patterns could therefore be the equivalent of algae blooms.

Venus is thought to have once had water on its surface, potentially for as long as 2 billion years providing enough time for life to evolve. As the surface water evaporated the microorganisms could have been transported to the clouds, in similar ways to how bacteria have been found in the atmosphere of Earth (although on Earth aerial microbes do not appear to remain aloft indefinitely). Life on the second planet from the sun therefore remains a possibility and only further observations and potentially even atmospheric sampling will reveal whether the changing dark patches are indeed patterns of microbial life.

Original research: https://doi.org/10.1089/ast.2017.1783

March 29, 2018March 29, 2018

Egg quality

Low egg quality –

the impact of age. Blocking

proteins slows decline.

As women age their reproductive ability decreases due to declining egg quality. However, research by Templeman et al (2018) suggests that blocking a particular group of proteins may help to slow this decline, potentially extending the reproductive period.

The proteins, known as cathepsin B proteases, are more common in age-degraded oocytes (unfertilised eggs) and appear to be part of the problem of decreasing quality. By blocking the proteins in C. elegans worms oocyte quality was maintained for much longer, regardless of whether the drug was administered at the beginning or part way through the worms’ reproductive period. Whilst it’s not ready for testing with humans, it points the way towards an interesting new approach.

Original research: http://dx.doi.org/10.1016/j.cub.2018.01.052

March 27, 2018March 27, 2018

Crop blighter

Rice blast: crop blighter.

Inhibiting one protein

stops the fungal spread.

Up to 30% of rice crop is destroyed by rice blast every year, causing huge welfare and economic costs. Sakulkoo et al (2018) have found that inhibiting a single protein enzyme in the fungus stops the spread of the blight through a rice plant.

The fungus’s mitogen-activated protein Pmk1 plays a role in suppressing its host’s immune system and controls the ability of the fungus to move from one rice cell to another. By inhibiting Pmk1’s kinase the fungus is trapped within the infected rice cell and is unable to spread and infect the rest of the rice plant. This latest discovery could point the way towards new rice blast control methods, resulting in increased food security and economic development.

Original research: http://dx.doi.org/10.1126/science.aaq0892

March 13, 2018May 20, 2021

Reservoir or predator

African clawed frog –

reservoir or predator

of the fungal blight?

Amphibian populations worldwide are being devastated by a fungal infection (known as chytrid or Bd). As an invasive species and carrier of the fungal infection African clawed frogs are often blamed for the spread of chytrid and the current conservation crisis.

Research by Wilson et al (2018) suggests the story is more complicated than it at first seems though. Field studies in California suggest a 10% level of Bd infection in the frogs, with infected individuals having very low levels of infection. Additionally, larval clawed frogs appear to eat the Bd zoospores and may therefore actually be helping to reduce the negative impact and spread of the fungus. Unfortunately the study also suggests that the frog larvae also eat Daphnia, which are another predator of the Bd zoospores.

This latest research adds to growing evidence suggesting that African clawed frogs may not be as guilty as they seemed at first.

Original research: https://doi.org/10.1371/journal.pone.0191537

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

March 2, 2018March 2, 2018

When I talk about running

What I remember

when I talk about running:

Stress fading away.

Proponents of exercise have long sung its praises as a way of staying physically healthy, but there is increasing evidence that it has mental health benefits as well. Miller et al (2018) found that exercise (and specifically running) helped reduce the impact of chronic stress on the brain.

The scientists compared stressed and unstressed mice that either had access to a running wheel or not. Mice that were able to exercise mitigated some of the negative impacts of stress, whilst mice that were unable to exercise showed a reduction in the long-term potential of their hippocampal function (the part of the brain responsible for learning and memory).

In honour of World Book Day the poem references Haruki Murakami’s excellent meditation on running and life ‘What I Talk About When I Talk About Running’, which itself was a play on Raymond Carver’s ‘What We Talk About When We Talk About Love’.

Original research: https://doi.org/10.1016/j.nlm.2018.01.008

February 16, 2018February 16, 2018

Foibles of research

Manipulation?

Coercion? Unwanted guests?

Foibles of research.

Academia prides itself on being fair, rational-minded and logical. Yet the practice behind these noble aims is sometimes far from that. A study by Fong & Wilhite (2017) reveals the various manipulations that can take place: from scholars gaining guest authorships on research papers despite contributing nothing to unnecessary reference list padding in an effort to boost citation rate. These instances of misconduct are likely a response to the pressures of an academic career – the demand for high numbers of publications and citation rates.

The survey of approximately 12,000 scholars across 18 disciplines revealed that over 35% of scholars have added an author to a manuscript despite little contribution (with female researchers more likely to add honorary authors than male researchers). 20% of scholars felt someone had been added to one of their grant proposal for no reason. 14% of academics reported being coerced into adding citations to their papers by journals, whilst 40% said they’d padded their reference list to pre-empt any coercion. Whilst changes to aspects of the academic system might help alleviate these issues, it’s likely to be a slow process.

Original research: https://doi.org/10.1371/journal.pone.0187394

February 13, 2018May 10, 2019

Inbreeding Depression by Prof Fred W. Allendorf

More homozygous

brings inbreeding depression.

Cousins should not mate.

Inbreeding (mating between relatives) results in offspring having reduced fitness. This is known as inbreeding depression and is primarily caused by increased homozygosity at loci with harmful recessive alleles. Small populations, where most or all mates are relatively closely related, are particularly vulnerable to inbreeding and inbreeding depression. The effects of inbreeding depression in small populations can accumulate to reduce the population growth rate and increase the probability of extinction (Keller and Waller 2002).

Despite being of interest since Darwin, inbreeding depression remains a crucial area of research in conservation biology, ecology, and evolutionary biology. As global change, habitat destruction, and fragmentation rapidly progress, many natural populations will become smaller and more isolated and consequently more affected by inbreeding depression.

Original Research: Keller, L. F., and D. M. Waller. 2002. Inbreeding effects in wild populations. Trends in Ecology & Evolution 17:230-241. http://dx.doi.org/10.1016/S0169-5347(02)02489-8

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.

Enjoyed this sciku? Check out Fred’s other sciku: Genetic drift, Gene Flow, and Adaptation.

February 6, 2018February 6, 2018

On a knife edge

Life on a knife edge:

The metabolic demands

facing polar bears.

Polar bears rely on marine mammals such as seals which are high-fat prey. Despite the richness of their diet however, new research suggests that a reduction in the prey availability can have severe consequences on polar bear survival.

Pagano et al (2018) monitored nine free-ranging female polar bears over 2 years, measuring their metabolic rates, daily activity patterns, body condition and foraging success. They found that more than half of the bears had an energy deficit resulting from a high metabolic rate (1.6 times higher than previously assumed) and a low intake of the high-fat prey. As fragmentation of sea ice continues and seals become harder to catch the high metabolic requirements of polar bears is likely to become increasingly catastrophic for the species.

Original research: https://doi.org/10.1126/science.aan8677

February 2, 2018February 2, 2018

Bright baubles

Bright baubles – the toys

of our childhood. What dangers

lurk behind your joys?

Toys have to be versatile – they need to be interesting, fun, tough and safe. Plenty of toys are collector’s items, sold in second-hand stores or passed onto the next generation. Yet some plastic toys may have a hidden danger.

Turner (2018) analysed used plastic toys using x-ray fluorescence spectrometry. Hazardous elements, including lead, barium, bromine, cadmium and selenium, were found to be present in many of the toys. Among the worst offenders were Lego bricks from the 1970s which had high levels of cadmium (particularly the colours red and yellow), reflecting manufacturing processes at the time of production. Happily toy production is a lot safer nowadays.

Original research: http://dx.doi.org/10.1021/acs.est.7b04685

January 31, 2018January 28, 2022

Quality of Life at Seven Years Post-Stroke by Dr Michael J. Leach

Old stroke survivor

a life of low quality

yet high quantity.

A stroke, otherwise known as a cerebrovascular accident, is a serious health problem whereby blood flow to the brain is interrupted by a blocked or ruptured blood vessel. A stroke is life threatening and requires emergency medical attention. If an individual survives a stroke, then he or she may live with one or more long-term effects, such as memory loss, hemiplegia (i.e. paralysis on one side of the body), visual impairment, or speech problems. Such long-term effects can negatively impact on a stroke survivor’s quality of life across multiple domains: independent living, social relationships, illness, physical senses, and psychological wellbeing. While quality of life has been well studied in the short term after stroke, few studies have investigated quality of life among long-term stroke survivors.

In original research conducted as part of my Master of Biostatistics degree, I assessed quality of life at seven years post-stroke among people residing in the north-eastern suburbs of Melbourne. The validated Assessment of Quality of Life (AQoL) instrument was used to measure quality of life. In the AQoL instrument, scores range from -0.04 (worse than death) to 0.00 (death equivalent) to 1.00 (optimal). Among 1321 stroke cases with a mean age of 68 years, 413 (31% of stroke cases) were still alive at seven years post-stroke and 328 (79% of survivors) were assessed in my study. Of the 328 long-term stroke survivors assessed, 76 (23%) had very poor quality of life ranging from -0.038 to 0.100. Furthermore, 6% of patients had quality of life that healthy individuals deem worse than death (i.e. ranging from -0.038 to 0.00). The mean quality of life score at seven years post-stroke was 0.51. This score means that, if faced with the prospect of being an average seven-year stroke survivor, a given person in the general population would rather live in full health for half of his or her expected life span.

This research is important in that it highlights the dire need for interventions to improve quality of life in the long-term after stroke. Potentially modifiable factors associated with better quality of life in the long-term after stroke could be targeted to improve the quality of stroke survivors’ lives. In my original research, the potentially modifiable factors associated with better quality of life included lesser handicap and independence in activities of daily living (e.g. indoor mobility, dressing, and shopping). An example of a promising targeted intervention to improve post-stroke quality of life is cognitive training aimed at improving brain function. As cognitive training has been shown to make people more independent in activities of daily living over a five-year period, it is a promising intervention to improve quality of life in the long-term after stroke.

Original research:

Leach MJ, Gall SL, Dewey HM, Macdonell RAL, Thrift AG. Factors associated with quality of life in 7-year survivors of stroke. Journal of Neurology, Neurosurgery & Psychiatry. 2011; 82(12):1365-1371. http://dx.doi.org/10.1136/jnnp.2010.234765

Dr Michael J. Leach is an Australian health researcher, biostatistician, and poet with a PhD in Pharmaco-epidemiology and a passion for health humanities. Examples of his science poems are available online: https://imagesofhealth.wordpress.com/.

If you enjoyed this sciku, check out Michael’s other sciku ‘Drug-Induced Hip Fractures‘, ‘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.

January 26, 2018July 4, 2019

Sqeamish ossifrage by John Norwood

Delectable mouse

in defiance, stands to face

sqeamish ossifrage

The ossifrage, more commonly known as the bearded vulture, prefers to feed on dead animals, feeding predominantly on the bone marrow as opposed to the meat. It will on occasion kill living animals, with its main prey being tortoises which it drops onto rocks to break them open.

This haiku celebrates a defiant mouse but was inspired by a secondary meaning. In my study of cryptography, I recently de-crypted a challenge with the solution: ‘the magic words are squeamish ossifrage’ which, as it turns out, is a phrase frequently incorporated into the solution of cryptographic puzzles since 1977.

Further reading: The Magic Words Are Squeamish Ossifrage

John Norwood is a Mechanical Engineer working with Carbon, Inc. to revolutionize how things are made. His interests include old houses, yoga, baking, cryptography, and bluegrass music. You can follow him on Twitter under the handle @pryoga

Enjoyed this sciku? Check out some of John’s other work: Universal truth, The answer is none, God may be defined, With enough data, and Rivers cut corners.

January 23, 2018January 23, 2018

Beak trimming distaste

Beak trimming distaste,

yet long beaks lead to poor health.

Best of a bad bunch?

Sometimes it’s better to cause harm for the right reasons rather than allowing worse harm to occur. Egg-laying barn hens typically have their beaks trimmed to reduce pecking damage but this practice results in pain and sensory loss for the birds. As a result the practice of beak trimming is being debated worldwide and some countries have already banned it based on welfare concerns.

Riber and Hinrichsen (2017) compared the welfare of trimmed and non-trimmed flocks of hens across 10 separate farms and across 62 weeks. They found that beak trimming actually resulted in higher conditions of hen plumage, skin and keel bones, as well as decreased mortality. Whilst beak trimming seems distasteful, this evidence suggests that it may be the best option after all.

Original research: https://doi.org/10.3389/fvets.2017.00222

January 19, 2018January 19, 2018

Increase carpet tog

Cold stress avoided

in laboratory mice –

increase carpet tog.

Temperature is an important element of animal care and it’s crucial to ensure that captive animals don’t overheat or suffer cold stress. Laboratory mice are often housed with a floor substrate of wood chips which may be useful in reducing cold stress.

Freymann et al (2017) found that the depth of this floor material influenced mouse physiology. Specifically a deeper wood chip layer resulted in mice with reduced adrenal, liver, kidney and heart weights and an increased tail length. These traits have previously been observed in mice housed under warmer conditions suggesting that the deeper substrate material is acting as an insulator and could be used to reduce cold stress in this captive species.

Original research: https://doi.org/10.1177/0023677217694400

January 16, 2018May 10, 2019

Genetic drift by Prof Fred W. Allendorf

Unavoidable

Time and chance happen to all

Wright, genetic drift.

Genetic drift is one of the primary mechanisms of evolution. It is the change in allele frequencies in a population between generations due to the sampling of individuals that become parents and the random binomial sampling of alleles during meiosis. The theory of genetic drift was primarily developed by Sewall Wright.

Genetic drift causes the loss of genetic variation, and it is more pronounced in small and isolated populations. The ongoing human-caused loss of habitat has brought about the loss of genetic variation in many species throughout the world via genetic drift.

Original research:

Wright, S. 1931. Evolution in Mendelian populations. Genetics 16:97-159. http://www.genetics.org/cgi/reprint/16/2/97

Enjoyed this sciku? Check out Fred’s other sciku: Inbreeding Depression, Gene Flow, and Adaptation.

January 12, 2018August 14, 2018

Underground sound

Listening for sound

whilst deep underground requires

middle ears to hear.

Animals living in different environments will face different auditory challenges. To investigate how environment shapes evolution Koyabu et al (2017) compared middle ear morphology across terrestrial, aquatic and subterranean species from the order eulipotyphla (including hedgehogs, moles and shrews).

They found that a subterranean lifestyle involved adaptations that allow for improved sound transmission at low frequencies and reduced transmission of bone-conducted vibrations. The adaptations observed included “a relatively shorter anterior process of the malleus, an enlarged incus, an enlarged staples footplate and a reduction of the orbicular apophysis”.

Original research: https://doi.org/10.1098/rsos.170608