Recently, I received the honourable request to comment on an article about the rewilding of captive Asian elephants. It’s not a topic I am very familiar with, so writing this commentary actually became a wonderful learning experience for me.
Several strong commentaries from cultural, ethical and psychological perspectives were already written. Here I tried to also add a relevant ecological & evolutionary perspective, focussing on the behavioural ecology of Asian elephants and their functional role in the ecosystem.
Abstract:Baker & Winkler make a thought-provoking contribution to the discussion of what role captive animals could play in nature conservation and how we could get there through rewilding. There certainly is potential for captive Asian elephants, Elephas maximus, to become targets of conservation efforts, but there are also many questions: (1) How much do (behavioural) traits of captive-origin animals differ from their free conspecifics? (2) What predicts the likelihood and strength of social reintegration of captive animals into free populations? (3) How much of an Asian elephant’s functional role in the environment can captive animals still fulfil and how may this influence the evolutionary dynamics of Asian elephant populations? These questions are challenging, but also an opportunity to gain crucial knowledge and insight into the elephant’s ecological role, as well as our own.
If you are interested in reading the complete commentary (approx. 1000 words) see here.
Just how much of a sensitive topic this particular case study is, we noticed by how difficult it was for us to find contributors. Luckily we found two experts from Moral Philosophy that shared their insight with us:
Carlos Gray Santana is an Assistant Professor in Philosophy at the University of Utah. Dr Santana’s uses ethics to shed light on complicated issues such as the environment and human cognition. William S. Lynn is a Research Scientist in the George Perkins Marsh Institute at Clark University. The focus of Bill’s work is the ethics and politics of animal protection and sustainability.
For optional guidance, we asked the experts the following questions:
Why is the matter of cats and wildlife so controversial?
Why do you think politicians focus on culling cats rather than on habitat loss (as suggested in Doherty et al. 2019) and could open discussions be fostered to move beyond culling?
How do you think the public would respond when culling of cats turns out not to be effective in halting endemic species decline?
Curious about what they had to say? Read our blog post here.
And you can also follow us on Twitter!
When it comes to finding patchy and sporadic food resources, being at the right place at the right time is of the essence. Our recent paper published in the Journal of Animal Ecology provides experimental field evidence that male guppies (Poecilia reticulata), in the presence of females, more often reach sporadically available food patches. In contrast, female guppies did not reach more (or less) food patches in the presence of males.
“Imagine you are in a new city and looking for a place to have a good meal, what do you do? You can walk around and see what restaurants you encounter, but chances are that this will take a lot of time and you might still end up at a mediocre place. Alternatively, you can see where others are going. When you have incomplete information about your environment, taking advantage of the information of others (i.e. social information) can be incredibly helpful.”
Many animals find themselves in situations of incomplete information about where to find resources, for example, because important resources are patchy and sporadically distributed. One such animal is the Trinidadian guppy.
Trinidadian guppies live in rainforest streams. Those guppies that live in the resource-poor sections of the streams can take advantage of high-quality food resources, such as fruits and insects that fall sporadically into the water. But such resources are difficult to find. Interestingly, a previous study we discovered that guppies that spent more time near others were more successful in locating these unpredictable food resources. Possibly, spending time with conspecifics results in greater exposure to social information about when and where to find important resources.
But in this study, we also found that males reached more food patches than females, particularly males that were in groups with proportionally more females. The presence of females may have increased the time male guppies spent socially and consequently affected how many novel food patches they reached.
To experimentally test if sex composition indeed influences social time and food discovery, we conducted a new study in which we manipulated the guppy sex compositions (all male, all female or mixed) in the wild. For a total of 18 experimental guppy groups, we performed social observations and foraging trials.
First, we tested whether sex composition affected food patch discovery in individual males and females. This was true for males, which reached more food patches when there were females present. Females reached a similar number of patches either with or without males present. Second, we tested whether sex composition affected the time an individual male or female spent socially. The variation in time spent socially mirrored variation in patch discovery, with males spending less time socially in the absence of females, but no effects again for females. Third, we analysed if this time spent socially was linked to patch discovery success. Indeed, in agreement with our previous study, more social guppies reached more food patches.
Conclusion: The foraging success of an individual thus depended on a combination of its own sex and the sex composition of its social environment.
Take home message: When hungry—and male—spending time in the company of females can get you at just the right place at the right time.
Our newest open access paper on repeatability of avian signalling (song) traits just came online in the journal Frontiers in Zoology.
Repeatability, consistent individual differences, in signalling behaviour is interesting because it means that those receiving the signal (i.e. listening to the song) could reliably learn something about how the individual singer compares to other singers/competitors.
We repeatedly recorded the dawn song of great tit males throughout the breeding season and show that start time of dawn song and repertoire size are individually repeatable both before and during the egg-laying stage of the mate (when she is fertile). Surprisingly the time a male started singing appeared to be more repeatable (consistent) than repertoire size, despite that the start time was also influenced by variable overnight temperatures. Start time was also more repeatable before than during egg-laying and we suggest that this is related to the behaviour of the (assumingly) intended receivers of the song, the females.
For a subset of the singers, we also explored a potential link between the absolute song trait values, the repeatability of these values and personality. We did not find a link but follow-up studies with a larger sample size, and including additional song traits, will be needed to confirm the true absence of such a link.