Reduction of predation risk under the cover of darkness: Avoidance responses of mayfly larvae to a benthic fish

Abstract

Mayfly larvae of Paraleptophlebia heteronea (McDunnough) had two antipredator responses to a nocturnal fish predator (Rhinichthys cataractae (Valenciennes)): flight into the drift and retreat into interstitial crevices. Drift rates of Paraleptophlebia abruptly increased by 30 fold when fish were actively foraging in the laboratory streams but, even before fish were removed, drift began returning to control levels because larvae settled to the substrate and moved to areas of low risk beneath stones. This drifting response was used as an immediate escape behavior which likely decreases risk of capture from predators which forage actively at night. Surprisingly, drift most often occurred before contact between predator and prey, and we suggest that in darkness this mayfly may use hydrodynamic pressure waves for predator detection, rather than chemical cues, since fish forage in an upstream direction. Although drifting may represent a cost to mayfly larvae in terms of relocation to a new foraging area with unknown food resources, the immediate mortality risk probably out-weighs the importance of staying within a profitable food patch because larvae can survive starvation for at least 2 d. In addition to drifting, mayflies retreated from upper, exposed substrate surfaces to concealed interstitial crevices immediately after a predator encounter, or subsequent to resettlement on the substrate after predator-induced drift. A latency period was associated with this response and mayflies remained in these concealed locations for at least 3 h after dace foraging ceased. Because this mayfly feeds at night and food levels are significantly lower in field refugia under stones, relative to exposed stone surfaces, predator avoidance activity may limit foraging time and, ultimately, reduce the food intake of this stream mayfly.

Community-Wide Consequences of Trout Introduction in New Zealand Streams

“…These patterns suggest that fish constrain activity of grazing invertebrates, whereby the distances that insects venture from refugia differ according to fish species. This interpretation would be consistent with findings that fish modify stream invertebrate behaviors and limit the amount of time foragers spend on exposed surfaces outside of refugia (e.g., Kohler and McPeek 1989, Culp et al 1991, Huang and Sih 1991, McIntosh and Townsend 1994.…”

Temporal and hierarchical spatial components of animal occurrence: conserving seasonal habitat for greater sage‐grouse

“…Taller shrubs may have functioned in reducing predation risk at night through concealment or impediment, or may have provided a generally favorable thermal environment in a landscape where cold temperature and high wind occur with frequency (sensu Guthery et al 2005). Temporal shifts in behavior have been noted across taxa and typically reflect differences between day and night in the accessibility of prey or forage resources, the risk of predation, or competition (Culp et al 1991, McMahon and Evans 1992, Reimchen 1998. In this and other human-modified landscapes, information on behavior across the diel cycle gives cause to view effective habitat loss as a spatiotemporal process rather than simply a spatial phenomenon; specifically, animals may select humanmodified landscapes at night but show strong avoidance of these areas during the day (Dzialak et al 2011a;2011b).…”

Causes and consequences of invertebrate drift in running waters: from individuals to populations and trophic fluxes

“…For instance, McIntosh and Peckarsky (2004) demonstrated that the mayfly Baetis bicaudatis adjusted its drift behaviour proportionally to the risk imposed by the odours of different fish predators. Studies have also shown Baetis to adjust its drift behaviour along gradients of fish density (Flecker 1992) and in response to simultaneous manipulations of predation and resources (Culp et al 1991;Culp 1994a, 1994b;Hoover and Richardson 2009). These results indicate that Baetis, a highly drift-prone taxa, has a moderately sophisticated response to balance foraging opportunities and predator avoidance using multiple environmental cues.…”