Geographic variation in breeding system and environment predicts melanin-based plumage ornamentation of male and female Kentish plovers

Sexual selection determines the elaboration of morphological and behavioural traits and thus drives the evolution of phenotypes. Sexual selection on males and females can differ between populations, especially when populations exhibit different breeding systems. A substantial body of literature describes how breeding systems shape ornamentation across species, with a strong emphasis on male ornamentation and female preference. However, whether breeding system predicts ornamentation within species and whether similar mechanisms as in males also shape the phenotype of females remains unclear. Here, we investigate how different breeding systems are associated with male and female ornamentation in five geographically distinct populations of Kentish plovers Charadrius alexandrinus. We predicted that polygamous populations would exhibit more elaborate ornaments and stronger sexual dimorphism than monogamous populations. By estimating the size and intensity of male (n = 162) and female (n = 174) melanin-based plumage ornaments, i.e. breast bands and ear coverts, we show that plumage ornamentation is predicted by breeding system in both sexes. A difference in especially male ornamentation between polygamous (darker and smaller ornaments) and monogamous (lighter and larger) populations causes the greatest sexual dimorphism to be associated with polygamy. The non-social environment, however, may also influence the degree of ornamentation, for instance through availability of food. We found that, in addition to breeding system, a key environmental parameter, rainfall, predicted a seasonal change of ornamentation in a sex-specific manner. Our results emphasise that to understand the phenotype of animals, it is important to consider both natural and sexual selection acting on both males and females

Scenario-oriented assessment of hazardous biological agents

The aim of this study is to elaborate a system that will enable easy, yet sound, communication between persons of different background on the topic of dangers and risks associated with the liberation of potentially hazardous biological agents. This system could then be used to assist planning procedures involving people with different professional backgrounds, e.g. for identifying, discussing and assessing possible gaps in security concepts and associated research needs. As a first step the feasibility of such a system assisting biological hazard assessment is tested, including the analysis of possible limitations

Nuptial feeding in the scorpionfly Panorpa vulgaris: Maintenance of genetic variance in sexual advertisement through dependence on condition influeincing traits

Missoweit M, Engqvist L, Lubjuhn T, Sauer KP. Nuptial feeding in the scorpionfly Panorpa vulgaris: Maintenance of genetic variance in sexual advertisement through dependence on condition influeincing traits. Evolutionary Ecology. 2008;22(5):689-699.In Panorpa vulgaris scorpionflies, females choose males on the basis of their saliva secretion ability depending on salivary gland weight. Condition dependent salivary gland weight indicates male quality in terms of food acquisition ability (FAA). In the present study we compare standardised estimates of additive genetic variance (V (a)) in conditional status and salivary gland weight under conditions including and excluding food competition. Estimates of V (a) were high when individuals compete for food and significantly lower when food competition was excluded, indicating that a large proportion of V (a) in conditional status as well as salivary gland weight attributes to V (a) in FAA. As FAA is likely to be determined by various underlying traits, maintenance of V (a) in FAA, and therewith in salivary gland weight, is easily conceivable. Furthermore, we found a strong genetic correlation between condition and salivary gland weight under conditions including food competition that decreased when food competition was excluded and thereby diminished the strength of sexual selection on condition influencing traits. In sum, our results demonstrate that estimates of V (a) in sexual signals (especially if estimated using standardised breeding conditions) will be strongly influenced by the presence/absence of environmental factors related to male performance in natural selection context

Functional Approach to Condition

Animal signaling is commonly thought to be costly. Signaling costs can arise via a variety of avenues, including energy expenditure, predator attraction, and so on (reviews in Zuk and Kolluru, 1998; Kotiaho, 2001), and are predicted to increase with signal expression (e.g., size, amplitude, and intensity; Johnstone, 1997). Due to these costs, signaler condition, which is hypothesized to be a reflection of a signaler’s genetic quality, is expected to influence the level of signal expression one can afford (Zahavi, 1975), resulting in a positive correlation between signaler condition and signal expression – that is, condition-dependent signaling (Zahavi, 1977; West-Eberhard, 1979; Andersson, 1982; Nur and Hasson, 1984; Zeh and Zeh, 1988; von Schantz et al., 1999). Despite the wealth of theoretical and empirical work on condition-dependent signaling, the term condition itself is somewhat enigmatic. An individual’s condition is a theoretical construct associated with the acquisition and allocation of nutritional resources, and is assumed to be an integral part of an individual’s health, vigor, and viability (Andersson, 1982; Nur and Hasson, 1984; Zeh and Zeh, 1988). Condition is often thought of as polygenic in nature, capturing much of the additive genetic variance responsible for viability, spanning numerous loci across the genome (Andersson, 1982; Rowe and Houle, 1996); however, like other quantitative traits, condition is also influenced by the environment as well as by interactions between an individual’s genotype and the environment (Hunt et al., 2004b). In this chapter, we use a widely accepted working definition of condition provided by Rowe and Houle (1996)−a pool of resources acquired from the environment, which is available for allocation to various fitness-related traits (see Figure 9.1). An individual’s condition sums numerous processes throughout its lifespan and is constantly fluctuating as resources are acquired and allocated to different functions (Figure 9.1). This broad definition of condition incorporates information on the resources available throughout an individual’s life−it encompasses the resources used during development to create structures (including those used for resource acquisition), the resources used in the normal functioning of an individual (i.e., its physiology), and the resources currently available in an individual’s energy stores (Figure 9.1). The decisions directing resource acquisition and allocation strategies (Figure 9.1) are ultimately influenced by both an individual’s environment (e.g., presence/absence of predators and food abundance) and its genotype (e.g., heritable traits related to foraging ability, digestion, and learning)