Male sand crickets trade‐off flight capability for reproductive potential

Abstract

In this paper, we test the hypothesis that male sand crickets, Gryllus firmus, experience a trade‐off between flight capability and reproductive potential expressed as reduced testis weight in flight‐capable morphs. We used a half‐sib design with 130 sires, three dams per sire and an average of 5.66 males per dam family, for a total of 2206 F1 offspring. Traits measured were head width, somatic dry weight, testis weight, wing morph (micropterous/macropterous), weight of the dorso‐longitudinal flight muscles (DLM) and the functional status of these muscles. Heritabilities of all traits were significant and ranged from 0.14 to 0.43. All traits were positively correlated with body size, but removal of this covariance revealed a highly significant trade‐off, both phenotypically and genetically, between testes size and flight capability as measured by wing morph, DLM size or DLM status. The possible implications of this for morph‐specific reproductive tactics are discussed.

Fitness Consequences of Infection by Batrachochytrium dendrobatidis in Northern Leopard Frogs (Lithobates pipiens)

“…If activation of the immune system during Bd infection draws on energetic resources that might otherwise be allocated toward muscle function or maintenance, then this could explain why some aspects of locomotor capacity decline in infected L. pipiens. Indeed, this explanation seems likely given that locomotor ability has previously been shown to be susceptible to resource allocation trade-offs in other animal species (see Zera and Harshmann (2001) for discussion; Saglam et al (2008) for an example). Given these two findings, repeating this experiment for a longer duration may uncover an even more pronounced effect of Bd infection on measures of whole-organism performance, particularly if immune activation is able to be maintained for a longer period of time than in this study.…”

Genotype by temperature interactions in the metabolic rate of the Glanville fritillary butterfly

“…The long-term persistence of the Glanville fritillary in fragmented landscapes is dependent on frequent dispersal between local populations and colonisation of new habitat patches (Hanski and Ovaskainen, 2000). Flight capacity may also have indirect consequences in the form of trade-offs with other energy-demanding processes such as reproduction (Nespolo et al, 2008;Saglam et al, 2008). The need for a high flight capacity may be reflected in the cost of maintenance, namely in the resting metabolic rate, but while a positive relationship between maximum and minimum metabolic rates is well established for vertebrates (Bennett and Ruben, 1979;Dutenhoffer and Swanson, 1996;Hinds et al, 1993;Walton, 1993;White and Seymour, 2004), it is less clear what this relationship is in invertebrates and in insects in particular (Niven and Scharlemann, 2005;Reinhold, 1999).…”

A performance-based cost to honest signalling in male green anole lizards (Anolis carolinensis)

“…Thus, the unreliable nature of the male signal in this species appears for the most part to depend not on the costs of signal production or maintenance, but on the cost of high-quality muscle production. Indeed, muscle is relatively costly to produce [24] and operate [25,26], and muscle production has been shown to trade-off against other important fitnessrelated phenotypes, such as fecundity [27] and testes size [28] in a variety of invertebrate species. Given these and other life-history trade-offs with physiological traits [26], costs of performance may potentially constrain or otherwise impinge on honest signal production.…”