Just a collection of random papers, theme issues and a blog that I thought looked pretty cool and that some people might find interesting.

First up, a paper about sexual conflict in a hemaphroditic species, plus it involves love darts! Snails have a really interesting mating system and this paper looks into how the costly behaviour of having love darts leads to conflict, sexual arms race and diversification of morphologies.

Kiruma & Chiba (2015) The direct cost of traumatic secretion transfer in hermaphroditic land snails: individuals stabbed with a love dart decrease lifetime fecundity. Proc R Soc B
http://rspb.royalsocietypublishing.org/content/282/1804/20143063

Next up, a themed issue on the biological impacts of artificial light, put together by Gaston, Visser and Holker. Its in Philosophical Transactions and my favourite paper in it is by Dominoni & Partecke called 
"Does light pollution alter daylength? A test using light loggers on free-rannging European blackbirds (Turdus merula)"
http://rstb.royalsocietypublishing.org/content/370/1667.toc

A paper about duetting in wrens. Using playbacks the authors show that females preferentially sing duets with mates to ward off intruders over singing overlapping songs with the 'intruding' female - which they do in the absence of their mate singing.


Templeton et al. (2015) Female happy wrens select songs to cooperate with their mates rather than confront intruders. Proc R Soc B
http://rsbl.royalsocietypublishing.org/content/9/1/20120863


Vocal duetting occurs in many taxa, but its function remains much-debated. Like species in which only one sex sings, duetting birds can use their song repertoires to signal aggression by singing song types that match those of territorial intruders. However, when pairs do not share specific combinations of songs (duet codes), individuals must choose to signal aggression by matching the same-sex rival, or commitment by replying appropriately to their mate. Here, we examined the song types used by female happy wrens (Pheugopedius felix) forced to make this decision in a playback experiment. We temporarily removed the male from the territory and then played songs from two loudspeakers to simulate an intruding female and the removed mate's response, using song types that the pair possessed but did not naturally combine into duets. Females were aggressive towards the female playback speaker, approaching it and overlapping the female playback songs, but nevertheless replied appropriately to their mate's songs instead of type matching the intruding female. This study indicates that females use song overlapping to signal aggression but use their vocal repertoires to create pair-specific duet codes with their mates, suggesting that duetting functions primarily to demonstrate pair commitment.



Lastly, a nice blog about sex ratios in bumble bees. Eusocial hymenoptera are fascinating, they have enthralled scientist for generations. Because of the asymmetric relatedness caused by haplodiploidy the conflicts and cooperation within these societies provide so many avenues for investigation and manipulation.


A little snippet from the blog: "Analysing my data I realised there were two types of colonies: those that quickly started to produce sexual individuals, and others that took much longer. The former invested much more in male production, whereas the latter mainly produced new queens. Hence, it appeared colonies adopted different strategies, and I hypothesised that both strategies could be equally successful, provided a population contains both."


https://blogs.royalsociety.org/publishing/sex-ratios-in-bumblebees-and-an-influential-experience/?utm_source=social_media&utm_medium=hootsuite&utm_campaign=standard--

This is not so much science as a bit of fun. This morning in the Daily Mail, I read it because it's part of my job not out of choice, was an article about choosing the national bird of Britain. This is apparently the brain child of David Lindo, the Urban Birder. The Mail makes many references to the majestic birds that other nations have as their symbol, the bald eagle of the US and Zambia's African fish eagle. These sound impressive birds, but national birds aren't always great: South Africa has the blue crane, it's a nice enough bird to see when your driving through the Overberg but it's hardly imperious. But I digress.

Here is Liindo's top 10 list (in a random order decided by the Mail):

1. Mute Swan Cygnus olor - pretty, but I've seen them attack rowers and they're very scary.
2. Red Kite Milvus milvus - having grown up in Thame, Oxfordshire, these birds fill me with joy. Hearing their cry on a summers day and watching them swoop over the garden or ride a thermal makes me think of home. A strong contender from me.
3. Hen harrier Circus cyaneus - lovely bird, but I've never seen one. I'd personally swap them for peregrines in this list, but that's because they're one of my favourite birds.
4. Puffin Fratercula sp. - they're great, and watching them fly is awesome but for some reason to me they feel Scandinavian, no idea why!
5. Barn owl Tyto alba - eerily majestic, but as we had a resident in our 'gym' in the Kalahari they will always remind me of Africa not Britain.
6. Wren Troglodytidae sp. - cheerful and cheeky, always fun to watch, a bit to much of an LBJ for a national bird (LBJ = little brown jobbie)
7. Kingfisher Alcedo atthis - nothing quite like the flash of blue on a river bank, but they're the symbol of cheep Indian beer at curry houses!
8. Robin Erithacus rubecula - boom, my vote! Cheeky little robin in the garden or the park, singing his heart out and they're pretty tenacious too.
9. Blackbird Turdus merula - I love black birds, seeing them whizz across suburbia calling as they swoop into a bush - reminds me of home.
10. Blue tit Parus caeruleus - very pretty, but perhaps a bit too pretty for us Brits. Lots of good research has been done on them though!


But there is one bird that isn't on the list and you could argue, given it's cultural importance to the UK - it's in the first song in the English language* - it should be. The cuckoo Cucculus canorus. Bringing me onto the awesome book that I've just bought written by Nick Davies about cuckoos: Cuckoo - cheating by nature. So excited to read it!!

*
Sumer is icumen in,
Lhude sing cuccu,
Groweth sed, and bloweth med,
And springeth the wode nu,
Sing cuccu!

This week I saw two papers that are different but deal, in an 'ultimate' nor 'proximate' way, with reproductive success and that I thought looked pretty cool.

The first is one that looks at extrapair mating and it's prevalence. This research is a meta analysis of studies related to looking at how genetically similar mated bird pairs are and how high the rates of extrapair paternity are. Unsurprisingly they find that when genetic relatedness is high then extrapair paternity is high. The novelty of this review is that is shines some light on why some previous work has failed to show this pattern, principally because they were looking at the wrong markers for genetic relatedness. Microsatellite markers were the best predictors. The females who are closely related to their behavioural mate is not surprising, it avoids inbreeding depression and has the potential for her offspring to have higher fitness. The part of this field that is truly interesting is how the female, or the male for that matter, knows they are closely related. Kin recognition is useful not only in cooperative breeding societies but also to avoid inbreeding, and birds presumably (from these results) are able to do this. A study on meerkats showed that relatives will and do mate with each other if they were not present in their natal group at the same time, but when this happens their offspring don't do as well as more outbred offspring. So there is a long-term fitness cost to sleeping with your relatives!

The second paper I saw looked at response and reward to seeing cute babies. The interesting finding of this work was that although there was no difference in how the women rated the cuteness of the babies faces, women who had higher 'maternal tendencies' got a higher reward from seeing the cuter babies.The language of the paper is not the easiest to read, this might be because Biology Letters papers are very short and so they've tried to cram everything in. It would be interesting to note if women's response change through their reproductive cycle or as they get older and are more likely to want to have children. There might be some sort of evolutionary adaptation to getting  a higher reward when you actually want children rather than when you don't want them.... who knows, more research is needed!


Arct et al. (2015) Genetic similarity between mates predicts extrapair paternity—a meta-analysis of bird studies. Behavioral Ecology doi: 10.1093/beheco/arv004

Extrapair mating has been recorded in approximately 90% of investigated avian monogamous species. However, factors triggering female mating decisions and potential fitness benefits from extrapair matings still remain poorly understood. Some studies suggest that females mate socially with low-quality males but seek extrapair mates offering superior genes for their progeny. This mating strategy may also help in mitigating the potential negative effects of pairing with a genetically similar mate. Here, we investigate whether genetic similarity within a social pair may predict the occurrence of extrapair paternity (EPP) in birds. Using a meta-analytical approach to a number of studies performed on birds, we found a positive relationship between the occurrence of EPP and the relatedness of social mates. Moreover, we found that the type of molecular markers used to estimate relatedness significantly affected the observed effect size. Specifically, we showed that only microsatellite markers were associated with significantly positive effect sizes. Thus, failure of some of the previous studies to detect the relationship between occurrence of EPP and the relatedness of social mates may at least partly arise due to methodological reasons.

http://beheco.oxfordjournals.org/content/early/2015/02/03/beheco.arv004.abstract

Hahn et al. (2015) Reported maternal tendencies predict the reward value of infant facial cuteness, but not cuteness detection. Biology Letters, DOI: 10.1098/rsbl.2014.0978

The factors that contribute to individual differences in the reward value of cute infant facial characteristics are poorly understood. Here we show that the effect of cuteness on a behavioural measure of the reward value of infant faces is greater among women reporting strong maternal tendencies. By contrast, maternal tendencies did not predict women's subjective ratings of the cuteness of these infant faces. These results show, for the first time, that the reward value of infant facial cuteness is greater among women who report being more interested in interacting with infants, implicating maternal tendencies in individual differences in the reward value of infant cuteness. Moreover, our results indicate that the relationship between maternal tendencies and the reward value of infant facial cuteness is not due to individual differences in women's ability to detect infant cuteness. This latter result suggests that individual differences in the reward value of infant cuteness are not simply a by-product of low-cost, functionless biases in the visual system.

http://rsbl.royalsocietypublishing.org/content/11/3/20140978