Strategies utilized by katydids (Orthoptera: Tettigoniidae) against diurnal predators in rainforests of Northeastern Peru
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Nickle, D. A., and J. L. Castner. 1995. Strategies utilized by katydids (Orthoptera: Tettigoniidae) against diurnal predators in rainforests of Northeastern Peru. Journal of Orthoptera Research 4:75-88.
Abstract:
More than 370 species of katydids have been identified and many of them observed over extended periods of time at three collecting sites in Loreto Province, Peru (40-160 km NW Iquitos). Defensive adaptations against diurnally active predators are reported in detail in this paper. Strategies include (1) primary defenses or adaptations to avoid contact with predators, including camouflage (e.g., green and brown color generalism, and bark-, twig-, lichen-, and leaf mimicry), concealment within leaf parts or forest debris, and territoriality in the form of defending roosting sites against other competing katydids, and (2) secondary defenses or adaptations used when contact is made with predators, including colorful displays by distasteful species, various forms of aggressive counterattacks, aposematic wasp mimicry, and visual and/or acoustical alarm displays by otherwise cryptic species. These strategies are quantified for the first time for an entire tettigoniid fauna in a neotropical rainforest habitat. Of the 378 species, 71.4% exhibited color generalism (208 green, 46 brown, and 19 with both green and brown morphs), 13.8% showed a more refined level of camouflage (2 wasp mimics, 5 bark mimics, 13 twig mimics, 29 leaf mimics, 4 lichen mimics), 4.8% were hidden from view during the day by concealing themselves within vegetation, debris, etc., and 9.8% could not be categorized because of lack of sufficient data based either on observations or relationships with similar species that had been observed. Most species with generalized color patterns were phaneropterines; most species with more specialized primary defenses of mimicry and concealment were either phaneropterines or pseudophyllines; while those with specialized secondary defenses were mainly listroscelidines, agraeciines, and copiphorines. All species that conceal themselves in debris, vegetation, etc. were observed returning just prior to dawn to the same site for up to twenty-one consecutive days; some of them were observed to successfully defend their roosting sites against other katydids. Twig mimics alter their substrates - twigs - by chewing notches on the undersides of the twigs and nestling their bodies into the depressions. Though exposed to view, katydids of these species are well concealed. They too return daily to the same site over a period of several consecutive days.
Keywords: mimicry, Phaneropterinae, Pseudophyllinae, Agraeciinae, Listroscelidinae, Copiphorinae, Conocephalinae