I remember a case in which some insect had evolved an adaptation in response to a predator's (bat's?) echolocation frequency. In mid-flight, it's wing muscles would become paralyzed and it would suddenly drop like a stone directly towards the ground. Does anybody know what this insect is? I thought it was a moth or a mantid.
Many different species react to bat echolocation sounds by altering their flight path or diving. This includes moths and mantids, but also other insects such as crickets, flying beetles, and likely many others as the following list (taken from this review by Miller and Surlykke (2001): How Some Insects Detect and Avoid Being Eaten by Bats: Tactics and Countertactics of Prey and Predator) is in no way exhaustive:
"Many bush crickets can hear bats, but few seem to react to bat echolocation. However, the bush cricket, Neoconocephalus ensiger, shows an acoustic startle response during tethered flight in the laboratory (Faure and Hoy 2000). When the insects hear intense batlike sounds with frequencies from 15 kHz to at least 60 kHz, they dive."
"Flying mantids (Parasphendale agrionina) react at distances as great as 10 m from a loudspeaker emitting batlike signals at natural intensities. They react by turning or with dives and spiral flight. The responses are all nondirectional, as would be expected from a functionally monaural system."
Flying scarab beetles
"In response to pulsed ultrasound, flying scarab beetles, Eutheola humilis, dropped or flew toward the ground, and walking beetles stopped."
"Freely flying, unidentified moths exhibit a variety of behavioral responses to bats and to synthetic batlike signals (Roeder 1967a; for recent results, refer to Acharya and Fenton 1992). Moths far from the source often turn and fly away, whereas those close to the source show zigzag and looping flight, power dives, or passive falls."
For a more recent review of the literature for the specific example of moths, I suggest reading Evolutionary escalation: the bat–moth arms race by Hofstede and Ratcliffe (2016).