Biology Archives - Page 7 of 9

January 10, 2018May 4, 2018

Equal rights for parasites by Donald A. Windsor

All over the Earth

Equal rights for parasites!

All life forms conserved!

Most of the species on Earth are parasites, so parasites are an
integral part of Earth’s biosphere. Parasites enable ecosystems to
function, mainly by preventing monocultures and generating
biodiversity. Therefore, it certainly seems prudent to conserve
parasites. Admittedly, parasites are not warm, fuzzy attractions and
even horrify most people. Consequently, conserving parasites is an
uphill battle. To cheer on supporters, I came up with the catchy
slogan, “Equal rights for parasites!”

Original research:

Windsor, Donald A. Equal rights for parasites. Perspectives in
Biology and Medicine 1997 Winter; 40(2): 222-229. https://doi.org/10.1353/pbm.1997.0011

Windsor, Donald A. Most of the species on Earth are parasites.
International Journal for Parasitology 1998 Dec; 28(12): 1939-1941. https://doi.org/10.1016/S0020-7519(98)00153-2

Windsor, Donald A. Parasites’ rights gaining ground. Nature 2017 December 21/28; 552(7685): 334. https://doi.org/10.1038/d41586-017-08873-3

Donald A. Windsor, a biologist with a multidisciplinary background, is
fascinated by the enormous impact parasites have on ecosystems. He
retired from industrial pharmaceutical research and development 23
years ago. He is currently affiliated with the Ronin Institute for
Independent Scholarship. His blog is:
http://www.parasitesdominate.blogspot.com/

Enjoyed this sciku? Check out Donald’s other sciku: Native American Dugout Canoe in Central New York.

December 20, 2017December 20, 2017

Transcription by Prof Sridhar Hannenhalli

To express or not

Here now a bit or a lot

That is the question.

Every cell in an organism contains an identical copy of the genome, except for rare somatic mutations, that encodes its entire gene complement. Yet, each of the hundreds of individual cell types in an organism utilizes a well-defined subset of the genes – imagine your neurons expressing genes that are normally expressed in skin cells. Thus the cell, starting from the single-celled embryo, must have a mechanism to control when, and how much of, each gene is expressed. This control is exercised, in large part, at the level of transcription – the process of reading the DNA encoding a gene on the genome and copying it into a messenger RNA (mRNA), which is eventually translated into the final protein product (or otherwise processed into a final RNA product).

Besides controlling normal development and defining the identity of individual cells, the response to a change in environment is also managed at the level of transcription. This was first demonstrated by Jacques Monod and Francois Jacob in their seminal 1961 paper, showing that a group of E. coli genes that encode for proteins required to break down lactose is transcriptionally switched on or off depending on whether the growth medium is rich in lactose or glucose. They went on to win the 1965 Nobel Prize in Physiology or Medicine for their discovery.

Transcriptional control plays a critical role not only in development and environmental response, but also at a longer time scale in mediating evolutionary divergence across species. In their classic 1975 paper, Mary-Claire King and Alan C Wilson, observing very high levels of similarity between several proteins of chimpanzees and humans, concluded that the vast phenotypic differences between the two species could not be explained by such small degree of molecular divergence and are likely to be driven by the changes in the mechanisms controlling the gene transcription.

The role of transcriptional control in dictating natural diversity at multiple natural scales from cells within an organism, individuals within a species, and across species is now well established. This extends even to phenotypic changes associated with all complex diseases, and is underscored by the observation that the vast majority of genotypic signals associated with human diseases reside in non-protein-coding regions of the genome, thus focusing the research efforts in interpreting these signals in the context of transcriptional control.

Original research:

Jacob, F. & Monod, J. (1961) Genetic regulatory mechanisms in the synthesis of proteins. J Mol Biol 3, 318–356. http://biotheory.phys.cwru.edu/phys320/JacobMonod1961.pdf

King, M. C. & Wilson, A. C. (1975) Evolution at two levels in humans and chimpanzees. Science (80) 188, 107–116. https://doi.org/10.1126/science.1090005

Hindorff, L. A. et al. (2009)Potential etiologic and functional implications of genome-wide association loci for human diseases and traits. PNAS 106, 9362–9367. https://doi.org/10.1073/pnas.0903103106

Sridhar Hannenhalli is professor of Cell Biology and Molecular Genetics at the UMD, interested in transcriptional regulation and evolution. He is currently visiting IISc, Bangalore, as a Fulbright scholar. You can follow him on twitter @hannenhalli.

December 18, 2017December 18, 2017

Exploiting blind spots

Tropical clawed frogs –

what you can’t see can’t hurt you.

Exploiting blind spots.

Providing sufficient shelter for animals in captivity is frequently an important method to improve welfare, however cover may limit the ability to observe animals for health checks. Western clawed frogs (or tropical clawed frogs) are a common model organism, kept in high numbers in laboratories around the world, but there is comparatively little empirical evidence for how best to adequately house this species in captivity.

Cooke (2017) found that a black overhead cover was the optimal method of providing refuge for this species. In a second experiment exploiting the frog’s inability to see certain wavelengths the black cover was swapped for a red translucent cover which was found to be just as effective.

Red translucent covers could therefore be an effective method of providing refuge for the animals whilst simultaneously allowing carers to observe and conduct health checks.

Original research: https://doi.org/10.1177/0023677217737798

December 8, 2017December 8, 2017

Packaging signals by Maria White

Packaging signals:

Limiters of gene exchange

in influenza.

Influenza viruses, which have segmented genomes, can exchange genes through a process called reassortment, which can lead to the formation of novel influenza viruses. At the termini of each gene segment are regions called packaging signals, which direct the incorporation of each gene segment into virus particles during assembly.

A recent study by White et al (2017) demonstrated that heterologous packaging signals limit the efficiency of reassortment, but that this phenotype is dependent on the influenza virus gene segment being examined.

Of note, 85% of the reassortant viruses studied packaged a hemagglutinin (HA) segment carrying matched packaging signals relative to the background of the virus. The HA segment is of particular interest from a public health perspective due to its antigenic properties, and these data suggest that HA packaging signals could be an important factor in determining the likelihood that two influenza virus strains will undergo reassortment.

Original research: https://dx.doi.org/10.1128%2FJVI.00195-17

Maria White is a PhD candidate in the Immunology and Molecular Pathogenesis program at Emory University.

December 5, 2017July 18, 2019

Closing the trap by Dr Hortense Le Ferrand

A feather falling –

hungry inert soul wakes up,

snaps, closing the trap.

The Venus flytrap, Dionaea muscipula, is a carnivorous plant that performs one of the fastest movements in the flora: when an insects touches the hairs inside the leaves of the trap, it closes in a few milliseconds.

Inspired by the plants and its internal microstructure, a team of researchers from ETH Zürich and Purdue University have developed a composite material mimicking the Venus leaf and able to change shape as fast as the plant (Schmied & Le Ferrand et al, 2017).

Thanks to the good match between the theoretical simulations and the experimental results, their method opens new avenues for the creation of autonomous and fast robotic devices.

Original research: https://doi.org/10.1088/1748-3190/aa5efd

Dr Hortense Le Ferrand is a postdoctoral fellow 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 other scku ‘Shrimp molting’ here.

November 24, 2017December 11, 2017

Dark moths by Prof Matthew J. James

Industrial soot

Biston betularia

Quo vadis dark moths?

The Peppered Moth (Biston betularia) is a classic example of evolution in action, yet in recent years Darwin’s Finches seem to have eclipsed the Peppered Moth as the textbook example of natural selection.

This sciku, written by Professor Matthew J. James, celebrates the Peppered Moth as an example of rapid natural selection and asks where the dark moths are going, Quo vadis in Latin meaning “Where are you going?”. The question refers to both the population change in moth colouration from dark to light and also implies a nostalgic deeper meaning asking where the Peppered Moth explanation of natural selection has gone in light of the present-day dominance of Darwin’s Finches.

The wild-type Peppered Moth has light wing patterns that act as effective camouflage against its common environmental background. Industrial smog from 19th century coal burning in the United Kingdom resulted in the trees upon which they rested becoming blackened by soot, making the moths stand out. As a result the population of light-winged moths plummeted due to increased predation, however numbers of the melanic mutant form (black in colour) of the species rose – this process has been termed Industrial Melanism. As the Industrial Revolution waned and levels of pollution decreased, numbers of the light-winged form of the moth rose once again. Cook & Saccheri (2013) present an interesting review of the Peppered Moth as a natural selection case study.

Original research: https://dx.doi.org/10.1038%2Fhdy.2012.92

Professor Matthew J. James is Chair in the Department of Geology at Sonoma State University, California. His recent book, Collecting Evolution, examines a scientific collecting expedition to the Galapagos Islands in 1905-06 that resulted in the concept of Darwin’s Finches being developed by David Lack in his 1947 book by that same name.

November 20, 2017November 20, 2017

Food or family?

Learning to distinguish kin

is hard with prey near.

The benefits of recognising your relatives are many and in cannibalistic species can include avoiding eating members of your own family. Learning kin cues frequently occurs early in life when a number of other cues need to also be learnt, including food cues.

Christiansen and Schausberger (2017) found that predatory mites raised with only their relatives were able to distinguish between related and unrelated larvae. This distinction was not made by mites reared in the presence of relatives and food cues.

The presence of food cues interfered with the learning of kin cues, yet the presence of kin cues did not disrupt the learning of food cues. This suggests that if food is present the mites will learn to identify it, however if there is no food and the mites may need to resort to cannibalism then they learn to avoid eating their own relatives.

Original research: https://doi.org/10.1016/j.anbehav.2017.09.005

November 15, 2017March 25, 2021

A zoo without bars by Dr Lisa Holmes

A zoo without bars –

Building thoughtful habitats

for all to explore.

Chester Zoo (www.chesterzoo.org) is a registered conservation and education charity that supports projects around the world and closer to home in Cheshire. Welcoming 1.9 million visitors a year, it is the most visited zoo in the UK; home to over 15,000 animals and more than 500 different species, many of which are endangered in the wild.

Chester Zoo has continued with the ‘always building’ philosophy of our founder, George Mottershead, who created the UK’s first zoo without bars and focused on animal wellbeing and conservation. In 2015 Chester Zoo opened Islands which was the largest zoological development in the UK to date. The Islands expedition is an immersive experience, taking visitors through six South East Asian islands to discover the incredible wildlife native to those areas and highlight the conservation issues that the zoo staff are working hard to address.

Modern day zoo research encompasses many aspects of biological and social sciences with the overall aim to address challenges faced in the natural world. Chester Zoo not only supports conservation research both in- and ex-situ but leads on important projects both in the UK and across the globe to improve the management of animals and plants, influence sustainability of wild populations and inspire others to Act for Wildlife.

Lisa Holmes is the Behaviour and Welfare Scientist within the Applied Science team at Chester Zoo. Her role involves working closely with the animal curators and keepers to provide evidence-based recommendations to enhance animal wellbeing and help to inform enclosure design. Lisa supervises postgraduate and sandwich placement students who help to gather key data for a wide range of species. Lisa’s research team are currently working on a long-term project assessing the response of species which have moved into the new Islands habitats.

Check out Lisa’s latest sciku ‘The Masterplan’ here.

November 13, 2017November 13, 2017

An orphan crop

Yam: an orphan crop,

vital yet disregarded.

Gene map may assist.

Yams are a stable tuber crop in tropical Africa yet their cultivation has been constrained due to little interest from the rest of the world, their susceptibility to pests and diseases, and their awkward propagation. As such they can be referred to as an “orphan crop that would benefit from crop improvement efforts”.

To help the humble yam’s lot, researchers have sequenced the genome of the white Guinea yam (Tamiru et al, 2017). The research has revealed that yams belong to a unique genus (Dioscorea) that is distinct from rice, palm and banana groups. Yams have separate male and female plants (a limiting factor for yam breeding efforts) but the research has now revealed that yams use female heterogametic sex determination – unlike our XX females and XY males, yams have ZZ males and ZW females meaning that it’s the female gamete that determines the sex of individual offspring. The research hopes to assist yam breeding and cultivation efforts as well as improve food security and sustainability.

Original research: https://doi.org/10.1186/s12915-017-0419-x

November 6, 2017November 6, 2017

Little peepers

Nocturnal Kiwi.

Redundant little peepers –

can survive blindness.

Most birds have excellent vision, even those that are active under low light conditions. In contrast the kiwi has the smallest eyes relative to body mass of any bird and poor vision. In fact, kiwis have been observed surviving in good condition in the wild despite being completely blind (Moore et al, 2017). Kiwis instead have sensitive auditory, olfactory and tactile somatosensory systems which they use to navigate the world and survive.

Original research: https://doi.org/10.1186/s12915-017-0424-0

November 4, 2017November 6, 2017

Swim in step

‘Let’s stick together,’

said the guppy to her friend,

‘we can swim in step.’

Shoaling in fish can provide safety from predators and increase the effectiveness of group movement. This group efficiency can be influenced by the behaviour of individuals within the group and a measure of group coordination is the extent to which animals align with one another – termed polarisation.

Investigating female guppies, Davis et al (2017) found that groups of familiar individuals were more polarised than groups of unfamiliar individuals. This was especially apparent when the groups were in novel surroundings and reduced with habituation to their surroundings. This increased coordination suggests that groups of individuals familiar with one another may be better able to cope with challenging situations.

Original research: https://doi.org/10.1098/rsos.170312

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.