Free-flight encounters between praying mantids (Parasphendale agrionina) and bats (Eptesicus fuscus)

Abstract

SUMMARYThrough staged free-flight encounters between echolocating bats and praying mantids, we examined the effectiveness of two potential predator-evasion behaviors mediated by different sensory modalities: (1) power dive responses triggered by bat echolocation detected by the mantis ultrasound-sensitive auditory system, and (2) ʻlast-ditchʼ maneuvers triggered by batgenerated wind detected by the mantis cercal system. Hearing mantids escaped more often than deafened mantids (76% vs 34%, respectively; hearing conveyed 42% advantage). Hearing mantis escape rates decreased when bat attack sequences contained very rapid increases in pulse repetition rates (escape rates <40% for transition slopes >16·p.p.s.·10·ms ) could circumvent mantis/insect auditory defenses. However, echolocation attack sequences containing such transitions occurred in only 15% of the trials. Since mantis ultrasound-mediated responses are not 100% effective, cercalmediated evasive behaviors triggered by bat-generated wind could be beneficial as a backup/secondary system. Although deafened mantids with functioning cerci did not escape more often than deafened mantids with deactivated cerci (35% vs 32%, respectively), bats dropped mantids with functioning cerci twice as frequently as mantids with deactivated cerci. This latter result was not statistically reliable due to small sample sizes, since this study was not designed to fully evaluate this result. It is an interesting observation that warrants further investigation, however, especially since these dropped mantids always survived the encounter.

Sonar jamming in the field: effectiveness and behavior of a unique prey defense

“…Studies of bats attacking insects around lights have typically not quantified the effects of lights on moth behavior and on the outcome of interactions (Acharya and Fenton, 1992;Acharya and Fenton, 1999;Rydell, 1992). In the present study (where 15W ultraviolet lights were used) we found no such effect, as the percentages of moths diving and being captured were independent of moth distance to ultraviolet lights (Fig.5) (Rydell, 1992); 4 Acharya and Fenton (Acharya and Fenton, 1999); 5 Triblehorn (Triblehorn et al, 2008); 6 present study; and 2004). We conclude that the use of low-wattage ultraviolet lights appears to be a valid method for attracting naturally behaving bats and moths for study.…”

“…Research documenting the pursuit and escape flight of bats and insects has largely been restricted to captive animals in controlled environments (Corcoran et al, 2010;Dawson et al, 2004;Ghose et al, 2006;Ghose et al, 2009;Triblehorn et al, 2008). Although these laboratory studies have yielded many novel discoveries, the limited space of a flight room prevents the animals from exhibiting the full suite of behaviors that occur in nature.…”

How moths escape bats: predicting outcomes of predator-prey interactions

“…It was not possible to determine how much of this variation came from differences between or within species, but an exciting future direction is examining how species-specific escape strategies relate to differences in flight morphology and turning ability. Moths and other insects often make dives when pursued by bats (Roeder, 1962;Triblehorn et al, 2008;Corcoran and Conner, 2012). A key component of this strategy may be using gravity to increase radial acceleration.…”

“…Behavioral observations of hunting barbastelles are required to determine whether prey evade too late or not at all. A rapid transition in bat echolocation behavior from search to buzz prevented mantids (Parasphendale agrionina) from initiating defensive responses (Triblehorn et al, 2008), so it may also be possible for bats that echolocate at high intensity to manipulate prey behavior.…”

“…Insect evasive maneuvers are highly complex, ranging from dives to loops, spirals and erratic flight (Roeder, 1962;Miller and Surlykke, 2001). Evasive maneuvers increase the probability of moths surviving attack (Acharya and Fenton, 1999;Triblehorn et al, 2008;Corcoran and Conner, 2012). However, it remains unclear what proximate factors determine whether insects escape attack.…”