There has been widespread concern that neonicotinoid pesticides may be adversely impacting wild and managed bees for some years, but recently attention has shifted to examining broader effects they may be having on biodiversity. For example in the Netherlands, declines in insectivorous birds are positively associated with levels of neonicotinoid pollution in surface water. In England, the total abundance of widespread butterfly species declined by 58% on farmed land between 2000 and 2009 despite both a doubling in conservation spending in the UK, and predictions that climate change should benefit most species. Here we build models of the UK population indices from 1985 to 2012 for 17 widespread butterfly species that commonly occur at farmland sites. Of the factors we tested, three correlated significantly with butterfly populations. Summer temperature and the index for a species the previous year are both positively associated with butterfly indices. By contrast, the number of hectares of farmland where neonicotinoid pesticides are used is negatively associated with butterfly indices. Indices for 15 of the 17 species show negative associations with neonicotinoid usage. The declines in butterflies have largely occurred in England, where neonicotinoid usage is at its highest. In Scotland, where neonicotinoid usage is comparatively low, butterfly numbers are stable. Further research is needed urgently to show whether there is a causal link between neonicotinoid usage and the decline of widespread butterflies or whether it simply represents a proxy for other environmental factors associated with intensive agriculture.

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Female mating preferences were studied in the seaweed fly, Coelopa frigida. The female acceptance/rejection response to the intial mount by randomly chosen males was scored and male mating success determined by the subsequent production of progeny. The sizes of males and females, as well as their genotypes at the alcohol dehydrogenase (Adh) locus, were determined. Both adult size and the Ad/i locus are known to be strongly associated with a large chromosomal inversion system. Stepwise multiple regression analyses revealed no association between male mating success and male Ad/i genotype, but a stong association was found with male size. Female mating preferences appear to exert strong directional selection in favour of large males. There was also an association between female acceptance rate and female Adh genotype, which is likely to be a consequence of inversion karyotype rather than the Adh locus. It is suggested that the discrepancy between the mean size of males in natural populations and the preferred male size indicates that the forces of natural (viability) selection and sexual selection act in opposition.

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In Daucus carota L. (Apiaceae) the florets comprising the central umbellet of inflorescences are usually pink or dark purple, presenting a marked contrast to the surrounding umbellets, which are generally white. The number of dark florets varies, and some inflorescences have no dark florets. It has been proposed that the dark florets function as an insect mimic, and in so doing serve to attract insects to the flower. In contrast, other authors, Darwin included, suggest that they are functionally redundant. The present study examined whether the dark florets attract insects, and also whether this effect can be replicated by replacing these florets with an insect. At the study site in Portugal the predominant insect visitor was the beetle Anthrenus verbasci L. (Dermestidae), which is similar in size and shape to the dark florets. Large inflorescences and those with more dark florets attracted more beetles than small inflorescences and those with fewer or no dark florets. Inflorescences with the dark florets removed attracted fewer beetles visitors compared with intact inflorescences. Inflorescences in which the dark florets were replaced with one or a cluster of five dead, freeze-killed A. verbasci attracted more beetles than inflorescences from which the dark florets had been removed. Replacement of the dark florets with a relatively large Meloid beetle resulted in the attraction of markedly fewer A. verbasci. We conclude that the dark florets can act as an insect attractant for some insect groups by acting as an insect mimic, and that they are adaptive, in contrast to the speculations of Darwin.

Field work and field courses within undergraduate biology degrees have been under threat in recent years for multiple reasons and while there has been widespread support from learned societies, academic staff and students for the retention of field study, there has been little research to support the perceived value of field teaching within this context. This paper reports on research that addresses this issue. Undergraduate attainment data from final-year biology undergraduates were compared with similar attainment data from their penultimate year of study. Those students who attended a 10-day residential field course in Portugal between their penultimate and final years of study were found to perform about a grade better on a 20-point scale compared with non-attending students in their final-year honours module. This research provides quantitative evidence that field courses can increase attainment and improve cognitive learning in undergraduate biology students.