New Journal of Zoology Podcast

28 07 2014

A new episode of the Journal of Zoology podcast is now available and you can listen to it here.

Journal of Zoology PodcastIn this episode, Laia Mestre tells us how predators by just their presence are able to affect the behaviour of their prey, such as when spiders change their behaviour when they detect ant cues in their environment. We will also hear from Georgia Cummings about a particular case of bat pollination in New Zealand and how unique such a phenomenon is in a temperate ecosystem, and we learn from Richard Holland what mechanisms and environmental cues migratory birds are using to navigate the globe in so-called ‘true navigation’.

You may subscribe in iTunes to receive the latest Journal of Zoology podcasts.

Elina Rantanen

Recently Published in the Journal

12 06 2014

Urban canyon effect: storm drains enhance call characteristics of the Mientien tree frog

Mientien tree frog calling in the drain (photo by Wen-Hao Tan)

Mientien tree frog calling in the drain (photo by Wen-Hao Tan)

Acoustic signals play fundamental roles in anuran communication by facilitating social interactions, and for many species, successful reproduction depends on long-range propagation and perception of advertisement calls. Several anurans have been shown to exploit habitat features, such as tree holes for their resonance effects, to improve mating call transmission. In an urban environment, such habitat features might also include man-made structures that animals learn to use for acoustic communication. In Taiwan, male Mientien tree frogs Kurixalus idiootocus frequently perch and call in roadside concrete drainages, suggesting that they are using these anthropogenic structures to assist call transmission. The authors of a paper recently published in Journal of Zoology tested this assumption by a combination of field and indoor experiments. Wen-Hao Tan et al. conducted a field survey of whether male Mientien frogs preferred calling inside the storm drains than outside them, and a playback experiment in the field to verify whether the propagation of calls emitted inside drains is enhanced. They also constructed a replica of a concrete drain in the lab to study whether male frogs selected perches inside the drains that facilitated better call transmission.

Field work in action (photo by Y. Kirk Lin)

Field work in action (photo by Y. Kirk Lin)

The field survey indicated that male Mientien tree frogs preferred calling inside rather than outside drains, and the playback experiment showed that calls emitted from inside drains were enhanced in both amplitude and note duration. The lab experiment showed that males preferred a particular type of call perch, although there was no difference in sound properties between random locations inside the drain model and the preferred perch location. Although it still needs to be verified whether the enhanced call transmission of male Mientien frogs calling inside the storm drains also means that they have better mating success, with these ‘urban canyons’, this study shows a novel effect of anthropogenic structures on bioacoustics.

This paper has recently featured in Nature News, Discovery News and several other news sites across the globe.

Elina Rantanen

New Journal of Zoology Podcast

9 04 2014

Journal of Zoology PodcastA new episode of the Journal of Zoology podcast is now available and you can listen to it here.

In this episode, David Hone tells us how the behaviour of extinct animals like dinosaurs can be deduced from the fossil record, we learn from Tomasz Wesolowski about parasites that manipulate the behaviour of their hosts for their own advantage, and Gus Mills talks to us about their new findings on cheetah cub mortality and how they affect conservation planning for cheetahs.

You may subscribe in iTunes to receive the latest Journal of Zoology podcasts.

Elina Rantanen

Hidden Gem

6 03 2014

The Experimental Proof of the Protective Value of Colour and Markings in Insects in reference to their Vertebrate Enemies

This ‘hidden gem’ from 1887 published in the Proceedings of the Zoological Society of London, the predecessor of Journal of Zoology, is an article written by E.B. Poulton about aposematism before he actually introduced the term in his book The Colours of Animals, published in 1890. It is essentially a review article summarising, comparing and discussing the existing data from various experiments testing Alfred Russel Wallace’s original idea of the use of warning colours in prey to put off predators from attacking them.

The article begins with a brief history of the idea, originating from correspondence between Darwin and Wallace. Puzzled by bright, conspicuous colours in caterpillars which could not possibly be explained by sexual selection, Darwin asked Wallace to suggest some other explanation and adaptive value for these bright colours. Wallace proposed that, as Poulton put it, ‘the gaudy colouring acts as an indication of something unpleasant about its possessor’, such as a nauseous taste or smell, and it would thus be to the advantage of the prey to be as conspicuous as possible to warn experienced predators of their foul qualities. Wallace’s idea had subsequently been tested and proven plausible. However, in this paper, Poulton points out that ‘the acquisition of an unpleasant taste or smell, together with a conspicuous appearance, is so simple a mode of protection, and yet ex hypothesi so absolutely complete, that it seems remarkable that more species have not availed themselves of this means of defence. What can be the principle which works in antagonism to such a mode of protection?’ As one explanation, Poulton proposes that this strategy would become less effective the more common it becomes among the prey, as predators might then start eating the foul-tasting prey if they would otherwise starve. It was indeed Poulton who introduced the idea of frequency-dependent selection in his later work, but he was clearly already contemplating this idea when he wrote this article.

This paper acts as a wonderful summary of the development of the theory of aposematism and is teeming with references to Wallace and Darwin as well as other famous names such as Bates and Müller regarding their respective theories on mimicry. It is available for free in our ‘Hidden Gems’ section of the Journal of Zoology website.

Elina Rantanen

Author Spotlight – Matt W. Hayward

27 01 2014

Matt HaywardPrey preferences of the lion (Panthera leo)

Matt W. Hayward & Graham I. H. Kerley, Journal of Zoology, 2006, vol. 267, pp. 309-322

Many years ago I moved to South Africa’s Addo Elephant National Park to conduct a post doc on the reintroduction of lions, leopards and spotted hyaenas there. The regional manager for SAN Parks was concerned that the lions would target valuable buffalo and posed a simple question to me – “What are they going to eat?”  I set about answering that question (and this video presents how I did that). Myself and collaborators at the Nelson Mandela Metropolitan University identified the preferred prey of lions and then extended this work to predict and test their diet at other sites. We then found that there was a tight relationship between the biomass of the preferred prey of lions and the density of lions themselves and there is a negative relationship between lion home range size and preferred prey biomass.  This information has been invaluable to conservation managers as they can now predict the diet, home range and carrying capacity of their large predator guild based on the suite of prey present at a site.

Since then, we have expanded this work to look at the rest of the African large predator guild, Eurasian predators and are now working on the prey preferences of American and Australian predators.  We now hold a database of prey preferences based on over 100,000 kills and we will use this to test various hypotheses relating to optimal foraging theory, mesopredator release and the impacts of invasive predators.  It’s an exciting time, but worth pointing out that this research is based on a plethora of natural history style studies and the demise of natural history makes the kind of meta-analysis that we are conducting very difficult in the future.  The publishing paradigm of only valuing high impact papers is not of particular benefit to practical biodiversity conservation.

Matt W. Hayward

New Journal of Zoology Podcast

17 12 2013

JZO Podcast Autumn 2013A new episode of the Journal of Zoology podcast is now online and you can listen to it here.

In this episode, Sara Helms Cahan talks to us about reproductive division of labour in eusocial species and how it emerged spontaneously in harvester ant queens in their lab experiment, we learn from Rudemar Ernesto Blanco how the ecology of extinct sabretooth predators could be deduced from their living analogue such as the southern short-tailed opossum, and Justin Carroll tells us about their field experiment comparing the effectiveness of two contrasting anti-predator strategies, crypsis and aposematism, using artificial prey.

You may subscribe in iTunes to automatically receive the latest Journal of Zoology podcasts.

By Elina Rantanen

Recently published in the Journal

10 12 2013

Cheetah cub survival revisited: A re-evaluation of the role of predation, especially by lions, and implications for conservation

It is widely held that cheetahs are prone to high cub mortality rates, mainly due to predation by lions.  This perception resulted from a landmark study on the Serengeti Plains, which found that only 4.8% of cheetah cubs survived, indicating that areas where large carnivores need to co-exist may not be suitable for cheetah conservation.  However, a recent study by Michael G.L. Mills and Margaret E.J. Mills, published in Journal of Zoology, has revealed that survival of cheetah cubs in the Kgalagadi Transfrontier Park was seven times higher than on the Serengeti Plains.  Although predation was the most common form of mortality, there was no evidence of lion predation, indicating that a range of other predators could also be involved.  Moreover, the authors suggest that scrutiny of the Serengeti data does not unequivocally prove the dominance of lions as predators of cheetah cubs there, and conclude that predation is an integral part of cheetah dynamics.

copyright Gus Mills

copyright Gus Mills

Importantly, the paper challenges the belief that cheetah cub mortality is always inordinately high, and that lions are their major predator.  The results suggest that cheetahs can potentially coexist successfully in protected areas with other large carnivores.  This paper sheds new light on ecological relations in carnivore community ecology that could influence long-term conservation planning for cheetahs.

Linda DaVolls


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