Inbreeding affects sexual signalling in males but not females of Tenebrio molitor

Abstract

In many species of animals, individuals advertise their quality with sexual signals to obtain mates. Chemical signals such as volatile pheromones are species specific, and their primary purpose is to influence mate choice by carrying information about the phenotypic and genetic quality of the sender. The deleterious effects of consanguineous mating on individual quality are generally known, whereas the effect of inbreeding on sexual signalling is poorly understood. Here, we tested whether inbreeding reduces the attractiveness of sexual signalling in the mealworm beetle, Tenebrio molitor, by testing the preferences for odours of inbred and outbred (control) individuals of the opposite sex. Females were more attracted to the odours produced by outbred males than the odours produced by inbred males, suggesting that inbreeding reduces the attractiveness of male sexual signalling. However, we did not find any difference between the attractiveness of inbred and outbred female odours, which may indicate that the quality of females is either irrelevant for T. molitor males or quality is not revealed through female odours.

Influence of Inbreeding on Female Mate Choice in Two Species of Drosophila

“…2). This pattern is consistent with results reported elsewhere showing preference for more heterozygous males (e.g., Ilmonen et al 2009; Bolund et al 2010; Zajitschek and Brooks 2010; Pölkki et al 2012). Our results also suggest that outbred females may have a more pronounced mating preference for outbred males than inbred females although these results were not significant.…”

“…A number of secondary sexual characteristics appear to have evolved via this sexual selection and a number of models have been proposed to describe the many facets involved (Andersson 1994; Palmer and Edmands 2000; Bonneaud et al 2006; Kempenaers 2007; Sherman et al 2008; Ilmonen et al 2009; Griggio et al 2011). Most often, the size or extravagance of secondary sexual traits are taken to be an indicator of general health and are most influential for mate choice, but more subtle aspects of potential partners associated with their genetic homozygosity or relatedness may themselves be under selection (Ilmonen et al 2009; Laloi et al 2011; Pölkki et al 2012). …”

“…Female mice ( Mus musculus musculus ) prefer the scent of outbred males to inbred males when both were infected with salmonella (Ilmonen et al 2009) and female mealworm beetles ( Tenebrio molitor ) prefer the scent of outbred males to inbred males (Pölkki et al 2012), but Aparicio et al (2001) found that males of spotless starling ( Sturnus unicolor ) with an intermediate level of heterozygosity were more successful in mating and reproduction than either of the extremes. These preferences may arise from reduced fitness in females who mate with inbred males instead of outbred ones as demonstrated in seed-feeding beetles (Fox et al 2012).…”

High Repeatability of Anti-Predator Responses and Resting Metabolic Rate in a Beetle

“…Since the response latency and the total time spent immobile did not significantly differ between the trials done in plastic containers and insect chamber, it means that one of those measurements may be omitted, which may save substantial amounts of time in future work on RMR and behavioral anti-predator responses. However, we do not recommend avoiding measurement of repeatability, because consistency of the two behavioral responses might be influenced also by genetic differences between animals (Foster and Endler 1999a, b;Buczkowski and Silverman 2006;Yamada et al 2009;Pölkki et al 2012) and properties of their environment such as ambient temperature (Prokkola et al 2013) or parasites (Ilvonen et al 2011). The high consistency of individual responses and the correlation between the responses might be explained by predation, which probably shapes the behavior of our semi-natural beetles.…”

A dark cuticle allows higher investment in immunity, longevity and fecundity in a beetle upon a simulated parasite attack

“…To avoid inbreeding effects (Polkki et al 2012), we mixed beetles taken from a long-term, over 10-year laboratory population maintained at the University of Tennessee, Knoxville (60 %), with beetles obtained from Big Apple Pet Supply (30 %) (Boca Raton, FL, USA) and those obtained from a natural population (10 %). We used the next generation of beetles for this study, which was maintained on a diet of chick starter mash supplemented with occasional vegetables and fruit, such as carrots, apples and potatoes.…”