Escape performance decreases during ontogeny in wild crickets

Abstract

SUMMARY Increasing the ecological relevance of studies relating to the performance of organisms has been a central issue for functional biologists over the last few years. Of particular concern are changes in performance throughout the life cycle as selective forces act differently on various life stages. We addressed this issue experimentally by following ontogenic variations in the escape performance of crickets threatened by artificial predatory signals. We measured their performance under natural settings, which is a necessary approach yet one that is undocumented in insects. We analysed numeric film sequences obtained using a high-speed video camera at 1000 frames s–1 to quantify wild cricket performance and behaviour in the field. We detected significant differences in cricket escape performance throughout ontogeny. Escape performances were higher in juvenile crickets than older instars. Complementary behavioural measurements for escaping crickets suggest that these variations may be related to the lower predatory risk perceived by large adults than by juveniles. We expect that our analysis of size-refuge will also improve our understanding in the development of performance, given its importance in community and population ecology theories.

When hatchlings outperform adults: locomotor development in Australian brush turkeys (Alectura lathami, Galliformes)

“…In the only other study of locomotor ontogeny in birds (chukar partridges), WAIR performance increased with age and was correlated with morphological and kinematic changes early in development (8 -20 days; [7]). However, there are few known examples where young outperform adults in escaperelevant behaviours: jackrabbits (Lepus; [4,5]), lizards (Anolis, [6]), crickets (Nemobius sylvestris [30]), brush turkeys (this study). It is likely that such developmental strategies evolved in response to high predation early in life (e.g.…”

Danger detection and escape behaviour in wood crickets

“…1A). The velocity and acceleration of the piston were accurately controlled using a computer (for more details see Dangles et al, 2006bDangles et al, , 2007. Two spot lights placed above the arena provide homogeneous illumination (2 spots of 230 V, 100 W white light).…”

Variability in Sensory Ecology: Expanding the Bridge Between Physiology and Evolutionary Biology

“…Fortunately, the last decade has witnessed an explosion of mobile and wireless technology that enables researchers to literally take the "laboratory into the field," and some sensory ecology research has already felt the advantage of these technological changes (e.g., vision research [Fleishman et al 1998 [Barth et al 1995;Dangles et al 2007]). This potential distinc- Frequency of eye cone classes were measured at different developmental stages in wild-caught black bream (Acanthopagrus butcheri) reared under two different lighting conditions.…”

“…In particular, this research showed that the loss of sound signals outdoors, especially when insects call within stands of vegetation, has forced insects to compensate by adapting specific behaviors such as redundancy calls or chorusing. More recently, Dangles et al (2007) used a portable simulator of spider air-flow signals to measure the sensory-mediated escape performance of crickets under field conditions ( Figure 4A, B). This experiment revealed that both the behavior and performance of evading crickets in nature, as well as the sensory pathways involved in such escape behavior, differ in several ways from observed laboratory performance.…”

“…Other key examples of wellstudied sensory systems include echolocation in bats and dolphins (Thomas et al 2002), electroreception in fish (Bullock et al 2005;Arnegard and Carlson 2005;Snyder et al 2007), hearing in frogs and insects (Wilczynski and Ryan 1988;Wiese and Gribakin 1992;Fullard and Yack 1993;Römer 1998;Stumpner and von Helversen 2001;Gerhardt and Huber 2002;Triblehorn and Yager 2005;Neuhofer et al 2008), mechanoreception in arthropods (Barth 2002;Suter 2003;Fields and Weissburg 2005;Triblehorn and Yager 2006), and magnetic field reception in birds and rodents (Kimchi et al 2004;Biro et al 2007), all of which have been examined in an ecological context. Sensory ecology has grown rapidly over the past decade, in part because of rapid technological advances, such as high-speed cameras (Buskey and Hartline 2003;Dangles et al 2007), field portable spectrometers (Cronin and Shashar 2001;Smith et al 2003;Johnsen 2007;Ryan 2007), panoramic image devices (Zeil et al 2003), acoustic flight path tracking (Jones and Holderied 2007), particle image velocimetry (Stacey et al 2002;Casas et al 2008), mathematical simulations (Humphrey et al 1993;Chittka 1996a;Magal et al 2006), and neural networks (Phelps 2007). Sensory ecology has also been incorporated into diverse areas of biology such as cons...…”