The potential influence of morphology on the evolutionary divergence of an acoustic signal

Abstract

The evolution of acoustic behaviour and that of the morphological traits mediating its production are often coupled. Lack of variation in the underlying morphology of signalling traits has the potential to constrain signal evolution. This relationship is particularly likely in field crickets, where males produce acoustic advertisement signals to attract females by stridulating with specialized structures on their forewings. In this study, we characterise the size and geometric shape of the forewings of males from six allopatric populations of the black field cricket (Teleogryllus commodus) known to have divergent advertisement calls. We sample from each of these populations using both wild-caught and common-garden reared cohorts, allowing us to test for multivariate relationships between wing morphology and call structure. We show that the allometry of shape has diverged across populations. However, there was a surprisingly small amount of covariation between wing shape and call structure within populations. Given the importance of male size for sexual selection in crickets, the divergence we observe among populations has the potential to influence the evolution of advertisement calls in this species.

Sexual selection and population divergence II. Divergence in different sexual traits and signal modalities in field crickets (Teleogryllus oceanicus )

“…Both traits were targets of sexual selection, but the form of selection differed between them, and also between two populations (Veltsos et al 2011). Pitchers et al (2014) found that wing morphology and acoustic signal properties covaried with differing strength in different populations of this species, but that overall covariance was minimal and appeared unrelated to patterns of population divergence. Pitchers et al (2014) found that wing morphology and acoustic signal properties covaried with differing strength in different populations of this species, but that overall covariance was minimal and appeared unrelated to patterns of population divergence.…”

“…In a similar study, Veltsos et al (2011) simultaneously estimated sexual selection on male calling song and olfactory profiles in the fruit fly Drosophila montana. A recent study tested the relationship between acoustic signals in a sister species of field cricket, Teleogryllus commodus, and morphological features of male forewings that contribute to their resonant properties (Pitchers et al 2014). A recent study tested the relationship between acoustic signals in a sister species of field cricket, Teleogryllus commodus, and morphological features of male forewings that contribute to their resonant properties (Pitchers et al 2014).…”

“…A recent study tested the relationship between acoustic signals in a sister species of field cricket, Teleogryllus commodus, and morphological features of male forewings that contribute to their resonant properties (Pitchers et al 2014). Such a pattern may be influenced by a greater degree of lability in behavioral traits compared to morphological traits that are fixed during development (Pitchers et al 2014;Ower et al 2016). Such a pattern may be influenced by a greater degree of lability in behavioral traits compared to morphological traits that are fixed during development (Pitchers et al 2014;Ower et al 2016).…”

Multivariate sexual selection on male tegmina in wild populations of sagebrush crickets, Cyphoderris strepitans (Orthoptera: Haglidae)

“…Not surprisingly, centroid size and dominant frequency negatively covaried, such that as the size of the tegmen increased, the area of the harp increased and correspondingly the frequency of the song decreased (Table ). The negative correlation between harp size and dominant frequency has been found in a large number of orthopteran taxa (Simmons, ; Simmons & Ritchie, ; Pitchers et al ., ). Pulse duration positively covaried with centroid size in both top and bottom tegmina (Table ).…”

“…In conclusion, we show that wing morphology has an important influence on song structure in C. strepitans and is subject to significant linear and nonlinear sexual selection through female precopulatory mate choice. Although numerous studies have documented the strength and form of sexual selection targeting song characteristics in crickets (Brooks et al ., ; Bentsen et al ., ; Oh & Shaw, ; Ower et al ., ), relatively few studies have examined the pattern of selection on wing morphology (Pitchers et al ., ), especially in wild populations. As song production is both a product of behaviour and the underlying morphology of the wing, understanding the link between morphology and behaviour is likely to have important implications for how song structure evolves.…”