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Seaweed flies
Photo: Maren Wellenereuther
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Role of cuticular hydrocarbons for mate choice in seaweed flies

Research project

Short description

The seaweed fly, Coleopa frigida, inhabits accumulations of seaweeds on the shoreline. Due to the activity of the fly larvae, these "wrack beds" decompose quickly. Evolutionary ecologist have long been interested in this seaweed fly species because of its inversion polymorphism on chromosome I. The inversion affects multiple traits that are important for the performance and fitness of the larvae and adult flies. Thus, choosing the right mate should increase fitness. In many insects, cuticular hydrocarbons are used as one of the primary cues to recognize, and possibly discriminate between species, sexes, and among kin. Within this projects we study the role of cuticular hydrocarbons for mate choice in the C. frigida system, using a combination of analytical techniques and behaviour experiments.

Members

Emma Berdan, Department of Marine Sciences – Gothenburg

Swantje Enge, Department of Marine Sciences – Tjärnö.

More about the project

The inversion polymorphism on chromosome 1 in C. frigida consists of two arrangements termed α and β. The inversion affects multiple measurable traits such as mating success, development time, and adult size. The maintenance of the inversion is mostly through balancing selection due to strong overdominance of the heterokaryotype (αβ). Heterokaryotypes are nearly always found in excess of Hardy-Weinberg expectations in natural populations and show higher viability than either homokaryotype (αα or ββ) under laboratory conditions, especially at high larval densities. Thus knowledge of the karyotype of the mating partner may influence mating decisions.

Cuticular hydrocarbons (CHCs) are used by many insects to recognize, and possibly discriminate between species, sexes, and among kin. Using GC/MS we recently showed that CHC composition is affected by both genetic (sex and population) and environmental (larval diet) factors and that males use CHC to recognise females. We are currently investigating the effect of the inversion on CHC composition and if these are involved in mate choice.