Ento ’13 conference and ladybird egg predation

Ento ’13 (the International Symposium and National Science Meeting of the Royal Entomological Society) took place at St Andrews University, Scotland at the beginning of September. It celebrated 30 years of Thornhill and Alcock’s The Evolution of Insect Mating Systems and contained several fascinating presentations from scientists around the globe, including Australia, Uppsala, Georgia and the UK. The afternoon talks (for the National Science Meeting) gave the opportunity for speakers ranging from PhD students to Professors to take the stage presenting their work in themed sessions (sexual selection, nuptial gifts, beneficial insects and a general session). Thursday night was the conference banquet and ceilidh. I’m not sure how many of the delegates had ever been to a ceilidh before, but a good amount gave it a go and there seemed to be smiles all round. I am happy to say I managed every dance, although I think that might be the most exercise I have managed so far this year! It was also a good opportunity to have a chat to those I had just met in a more informal manner.

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New fellows signing the obligations book, adding their names to others including Queen Victoria and Charles Darwin.

The poster session at Ento ’13 was held at lunch time on each day. This was my first time presenting a poster at a conference. I was very nervous about taking my poster along but in the end I ended up winning the second prize for a student poster, a huge surprise! The poster was based on egg cannibalism by ladybirds (work I had done as part of my masters back in 2011).  The invasive harlequin ladybird arrived in the UK approximately 10 years ago and has since spread rapidly through England. It is a very generalist species with a huge appetite and is easily able to out-compete native ladybird species for food and other resources. The harlequin ladybird is also able to cannibalise other ladybird species effectively, predating on the larvae and eggs of native species. The main aim of my study was to investigate the effect of harlequin eggs on a native species (the two-spot ladybird) after a single dose of eggs. Egg cannibalism is common in the field between most ladybird species and certainly occurs between these two species in the UK. Young two-spot ladybird larvae that were fed harlequin eggs had a survival rate of approximately 10%, compared to 70% when fed their own eggs. The harlequin larvae however maintained a high survival rate of above 67% when fed either conspecific or heterospecific eggs. There are two potential ways that harlequin ladybird eggs could cause this effect on the two-spot larvae. Firstly the eggs of most ladybird species contain alkaloids. It is possible that the specific alkaloids found in harlequin eggs are toxic to this native species. Secondly, this result could have been caused by a microsporidian parasite. Microspodidia has been found in harlequin ladybirds in Germany and was shown to be fatal to 7-spot ladybirds when they were given a dose of it, although harlequins appear to be resistant to this parasite. Either way the eggs of harlequin ladybirds had a detrimental effect to young two-spot ladybird larvae in this study.

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My poster from Ento’13

So the harlequin ladybird is very effective at being invasive: competition, cannibalism of other ladybirds and leaving behind toxins/mircosporidia in their eggs that will cause a detrimental effect for other ladybird larvae that cannibalise them. No wonder declines have been reported in some of our native species! But don’t all rush out and start killing harlequins! For a start, they are polymorphic, meaning that they have many colour forms, some of which look very similar to some of our native species. The best thing you can do if you see one is take a quick photo and send the record to the UK ladybird Survey (http://www.ladybird-survey.org/) which has been able to monitor the spread since the harlequin arrived in about 2004. They will be able to use the photo to confirm the ID and map the spread of the harlequin, and shifts in native species populations over time. You will also find if you have a smart phone that you are able to download an app that can do all of this, including taking your grid reference, for you!

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