Monthly Archives: April 2017

Pick and mix 2 – more eclectic links

Ten more links to peruse or not.

Not just British hedgehogs, but French hedgehogs are also on the decline

If you are a lover of Wisteria then this is definitely for you

A very thoughtful piece from Terry McGlynn on the ethical and moral stances that scientists take

Here is a report of a workshop run by an ex-PhD student of mine to discuss the future of farming insects for food in the UK

A really interesting paper describing how competition between two parasitic wasps can be influenced by the presence of an endosymbiont

Here is a paper of great relevance to farmers and policy makers but as usual has been published in a high impact journal that farmers and agronomists won’t read; as scientists we have to be more open to publishing in ‘lower scientific impact’ venues but that have a high impact in the real world

BioMed Central highlighting ways in which food crops might be protected against drought caused by climate change

According to Sir John Marsh the future of the countryside depends on economics

Chris Sandbrook asks what is meant by biodiversity in a conservation context

Like Manu Saunders I am a great believer in having others read my papers before submission, their chances of getting through the peer review process relatively unscathed are much improved

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Small and frequently overlooked, but without them we could not exist

Without them, we would find the world a very different place, that is if we were still alive.  Yet very few people give them a thought, and then usually only to dismiss them or castigate them for impinging on our comfortable lives. Animals without backbones, the micro-flora and fauna, are what keep the world a place in which we can make a living.  Politicians however, and many others of our fellow travellers on this fragile planet, seem unaware of their importance.  Donald Trump rescinds environmental protection laws as if they are a hindrance to humankind rather than a boon, BREXIT politicians and their supporters in the UK extol the virtues of escaping from those silly EU environmental laws that prevent them from polluting our beaches and rivers and making our air unbreathable. We all need to take a step back and adjust our vision so that we can appreciate the little things that run the world and understand that despite our size, our abundance and our apparent dominance, that we too are a part of nature.

I and many others have written about this topic on many occasions but it is a message that bears repetition again and again.  I leave you with the passage that stimulated my latest rant and a few links to similar pieces.

“In terms of size, mammals are an anomaly, as the vast majority of the world’s existing animal species are snail-sized or smaller.  It’s almost as if, regardless of your kingdom, the smaller your size and the earlier your place on the tree of life, the more critical is your niche on Earth; snails and worms create soil, and blue-green algae create oxygen; mammals seem comparatively dispensable; the result of the random path of evolution over a luxurious amount of time.”

Elizabeth Tova Bailey  (2010)  – The Sound of a Wild Snail Eating

Here are a few links to give you food for thought and to inspire you to find more of the same.

Michael Samways  Small animals rule the world. We need to stop destroying them

E O Wilson (1987) The little things that rule the world

Gregory Mueller & John Schmidt (2007) on why we should know more about fungi

Robert May (2009) Ecological science and tomorrow’s world

Mark Gessner and colleagues (2010) on the importance of decomposers

Anders Dahlberg and colleagues (2010) on why we should conserve fungi

Anne Maczulak (2010) on the importance of bacteria

Me complaining about plastic and other environmental dangers

Me again, this time about conserving small things

Sorry, but me again, this time about appreciating nature

and from Gerald Durrell, who was a great inspiration to me through his various writings…

And finally, If you haven’t read this, then I can certainly recommend it:

Ehrlich, P.  & Ehrlich, A. (1981) Extinction, Random House, New York.

 

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Pick and mix – eclectic links to stuff that caught my interest last week

Hopefully some of these links may be of interest to some of you.

 

Scientists, admittedly probably not all, can appreciate and enjoy poetry, as Stephen Heard points out here

On the Death’s Head Hawkmoth as a honey thief

For those of you who like France, bees and might be considering becoming beekeepers

On the value of native trees and shrubs for wildlife

On a similar vein, here is a paper about the value of native trees for insectivorous birds

More evidence of the importance of biodiversity for ecosystem functioning

The Journal of Biogeography celebrates the 50th anniversary of the publication of The Theory of Island biogeography by posing fifty fundamental questions that might take the discipline further forward

Another one from one of my favourite French sites, this time on the beauties of mosses and lichens

A French farmer asks for help from politicians using an ingenious message board

Over on Dynamic Ecology Jeremy Fox asks if you can think of any successful ecological models based on loose physical analogies?

And finally, announcing the launch of Pantheon, the tool to help you analyse your invertebrate species samples

 

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Sloth Moths – moving faster than their hosts

One of the minor downsides of our Biology and Taxonomy of Insects module on the MSc course is, that we do have to review a lot of families within some of the groups, Lepidoptera being a prime example.  Current estimates range from 250 000 to 500 000 species in 124 families (Kristensen et al., 2007). Going through the basic biology of each family can be pretty dry stuff, even if I have a personal anecdote or two to help lighten information overload.  I am, for example, able to wax lyrical for several minutes about small ermine moths and their incredible silk-production activities, but even after more than 40 years of playing around with insects I don’t have a personal story for every family of Lepidoptera 🙂 so I am always on the lookout for an extra interesting or mind-blowing fact to help leaven the student’s knowledge diet.

Imagine my delight then when I came across a clip* from a BBC One Wildlife programme, Ingenious Animals, describing an obligate association between sloths and moths and not just because of the rhyming opportunity** 🙂

Sloth with moths – BBC One Ingenious Animals

The earliest record of a moth associated with a sloth that I have been able to find is in 1877 (Westwood, 1877) which merely records that the unidentified moth was “parasitic on the three-toed sloth”. In 1908 a Mr August Busck on a visit to Panama saw a two-toed sloth, Choloepus hoffmanni fall from a tree and noticed several moths flying out of the sloth’s fur.  He caught these and on his return to the United States presented them to Dr Harrison Dyar (Dyar, 1908a).  If the name seems familiar to you that is because Harrison Dyar is better known in connection with Dyar’s Law, the observation that larval growth in arthropods is predictable and follows a geometric progression (Dyar, 1890). The moths were identified by Dyar as a new species which he named Cryptoses choloepi.  Dyar hypothesised that the moths and their larvae lived in the fur of the sloth and it was this that caused the sloth’s matted hair.

Cryptoses choloepi (Lepidoptera, Chrysauginae)

http://nmnh.typepad.com/department_of_entomology/2014/03/sloths-moths-and-algae-whos-eating-whom.html

Shortly after publishing the first note Dyar came across two more moth specimens, this time collected from a sloth in Costa Rica.  He felt that these were another species, possibly Bradipodicola hahneli (Dyar, 1908b).  The next mention of a sloth moth that I could fine is in a marvellously titled paper (Tate, 1931) who refers to a moth shot in western Ecuador whose fur was “literally alive with a small species of moth, whose larvae possibly fed on the greenish algae which grew in the hair”.  The idea that sloth moths fed on the fur of living sloths was further reinforced by Brues (1936) although this was not based on any personal observations.  It was only in 1976 that it was discovered that the larvae of the sloth moth Cryptoses choloepi were actually coprophagous (Waage & Montgomery, 1976), the female moths waiting for the three-toes sloth B. infuscatus to descend from the trees to relive their bowels, which they do about once a week.  As an aside, I have known Jeff Waage for many years in his role as a biological control expert but until I discovered this paper about a month ago, had no idea that he had ever spent time inspecting sloth faeces 🙂  Jeff and his co-author Gene Montgomery, described the association between the moths and the sloths as phoretic, rather than parasitic, as they saw no harm being caused to the sloths, but a number of benefits accruing to the moths, namely oviposition-site location being simplified, the fur of the sloth acting as refuge from avian predators and diet enhancement from sloth secretions (Waage, 1980).  It turns out however, that some species of sloth moth do spend their whole life cycle on the sloth, B. hahneli lose their wings once a sloth host is found and their eggs are laid in the fur of the sloth (Greenfield, 1981).  The algae that these moths presumably feed on is considered to be in a symbiotic association with the sloths, providing camouflage and possibly nutrition in the form of trace elements (Gilmore et al., 2001).  Hereby lies a tale.  The two-toed sloths have a much wider diet and home range than three-toed sloths and also defecate from the trees, unlike the three-toed sloths which have a very narrow diet (entirely leaves) and narrow home ranges, yet descend from the relative safety of the forest canopy to defecate, albeit only once a week, but still a risky undertaking (Pauli et al., 2017).  Rather than a phoretic relationship Pauli and colleagues see the relationship between sloths, algae and moths as a three-way mutualism, beautifully summarised in their Figure 3.

Postulated linked mutualisms (þ) among sloths, moths and algae: (a) sloths descend their tree to defecate, and deliver gravid female sloth moths (þ) to oviposition sites in their dung; (b) larval moths are copraphagous and as adults seek sloths in the canopy; (c) moths represent portals for nutrients, and via decomposition and mineralization by detritivores increase inorganic nitrogen levels in sloth fur, which fuels algal (þ) growth, and (d ) sloths (þ) then consume these algae-gardens, presumably to augment their limited diet. This figure brazenly ‘borrowed’ from Pauli et al. 2014).

The sloths take the risk of increased predation by descending to ground level, because by helping the moths they improve their own nutrition and hence their fitness.  Yet another great example of the wonders of the natural world.

 

Post script

Although not as exotic as the sloth moth, we in the UK can also lay claim to a coprophagous moth, Aglossa pinguinalis, the Large Tabby which feeds on, among other things, sheep dung.  In Spain it is recorded as a cave dweller feeding almost entirely on animal dung, apparently not being too fussy as to the source.

 

References

Bradley, J.D. (1982) Two new species of moths (Lepidoptera, Pyralidae, Chrysauginae) associated with the three-toed sloth (Bradypus spp.) in South America.  Acta Amazonica, 12, 649-656.

Brues, C.T. (1936) Aberrant feeding behaviour among insects and its bearing on the development of specialized food habits.  Quarterly Review of Biology, 11, 305-319.

Dyar, H.G. (1890) The number of molts of lepidopterous larvae. Psyche, 5, 420–422.

Dyar, H.G. (1908a) A pyralid inhabiting the fur of the living sloth.  Proceedings of the Entomological Society of Washington, 9, 169-170.

Dyar, H.H. (1908b) A further note on the sloth moth. Proceedings of the Entomological Society of Washington, 10, 81-82.

Dyar, H.G. (1912) More about the sloth moth. Proceedings of the Entomological Society of Washington, 14, 142-144.

Gilmore, D.PP., Da Costa, C.P. & Duarte, D.P.F. (2001) Sloth biology: an update on their physiological ecology, behaviour and role as vectors of arthropods and arboviruses.  Brazilian Journal of Medical and Biological Research, 34, 9-25.

Greenfield, M.D. (1981) Moth sex pheromones: an evolutionary perspective.  The Florida Entomologist, 64, 4-17.

Kristensen, N., Scoble, M.J. & Karsholt, O. (2007)  Lepidoptera phylogeny and systematics: the state of inventorying moth and butterfly diversity.  Zootaxa, 1668, 699-747.

Pauli, J.N., Mendoza, J.E., Steffan, S.A., Carey, C.C., Weimer, P.J. & Peery, M.Z. (2014) A syndrome of mutualism reinfocrs the lifestyle of a sloth.  Proceedings of the Royal Society B, 281, 20133006. http://dx.doi.org/10.1098/rspb.2013.3006.

Pinero, F.S. & Lopez, F.J.P. (1998) Coprophagy in Lepidoptera: observational and experimental evidence in the pyralid moth Aglossa pinguinalisJournal of Zoology London, 244, 357-362.

Tate, G.H.H. (1931) Random observations on habits of South American mammals.  Journal of Mammalogy, 12, 248-256.

Waage, J.K. (1980) Sloth moths and other zoophilous Lepidoptera.  Proceedings of the British Entomological and Natural History Society, 13, 73-74.

Waage, J.K. & Montgomery, G.G. (1976) Crytopses choloepi: a coprophagous moth that lives on a sloth.  Science, 193, 157-158.

Westwood, J.O. (1877) XXVIII. Entomological Notes.  Transactions of the Entomological Society, 25, 431-439.

 

*For the clip about the sloth moth see here http://www.bbc.co.uk/programmes/p04840xn

**Now, when I see a sloth,

My first thought is for the moth,

That has to make that desperate jump

When the sloth decides to take a dump!

 

 

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