The active metabolic rate predicts a male spider's proximity to females and expected fitness

Abstract

Conspicuous traits, such as weaponry and body size, are often correlated with fitness. By contrast, we understand less about how inconspicuous physiological traits affect fitness. Not only is linking physiology directly to fitness a challenge, but in addition, behavioural studies most often focus on resting or basal metabolic rates, resulting in a poor understanding of how active metabolic rates affect fitness. Here we use the golden orb-web spider (Nephila plumipes), a species for which proximity to a female on the web predicts a male's paternity share, to examine the role of resting and active metabolic rates in fitness. Using a semi-natural experimental set-up, we show that males closer to a female have higher active metabolic rates than males further from females. This higher metabolic activity is paralleled by increased citrate synthase activity, suggesting greater mitochondrial densities. Our results link both higher active metabolic rates and increased citrate synthase activity with fitness. Coupled with the behaviour and life history of N. plumipes, these results provide insight into the evolution of physiological systems.

Functional morphology of the respiratory organs in the cellar spider Pholcus phalangioides (Arachnida, Araneae, Pholcidae)

“…In other spider species, factorial scopes during locomotory activity are between 2 and 12, in Lycosidae sometimes even up to 22 for short periods (Anderson 1970;Culik and McQueen 1985;Ford 1977a, b;Humphreys 1977;Kotiaho 1998;McQueen 1980McQueen , 1981 Miyashita 1969;Seymour and Vinegar 1973;Shillington and Peterson 2002;Watson and Lighton 1994). Feeding, starvation and spontaneous activity resulted in factorial scopes of 4-7 in wolf spiders, tarantulas and in Nephila (Jensen et al 2010;Kasumovic and Seebacher 2013;Nespolo et al 2011;Tanaka and Itô 1982). As we measured our spiders without any influence of other spiders or prey, the resting metabolic rates will be real resting values.…”

Potential for CFC in Black Widows (Genus Latrodectus): Mechanisms and Social Context

“…This is particularly true because the ability of males to sustain prolonged, vigorous vibratory courtship prior to the first mating attempt may provide significant information about male traits such as metabolic competence, body condition, and juvenile provisioning (which reflects both development history and diet 10 Kasumovic et al 2009a;10 Stoltz et al 2012;Kasumovic and Seebacher 2013;10 De Luca et al 2015). Thus, CFC in Latrodectus may occur when female-mediated variation in male copulation frequency (equivalent to repeated mating success) is linked to some aspect of male phenotype, and those same traits are linked to the likelihood or frequency of the females copulating with a subsequent suitor.…”

Behavioral and physiological evidence that increasing group size ameliorates the impacts of social disturbance

“…). Indeed, a number of studies have shown that activities of specific metabolic enzymes correlate strongly with intense social behaviors in a range of animal systems (Gilmour et al, 2017; Guderley, 2009; Guderley and Couture, 2005; Kasumovic and Seebacher, 2013; Le François et al, 2005; Regan et al, 2015). In this study we focused on a key regulatory glycolytic enzyme (lactate dehydrogenase; LDH) and a key regulatory oxidative enzyme (citrate synthase; CS) that have been shown to reflect capacities for quick burst movements and more sustained aerobic activities, respectively (e.g.…”