Lack of correlation between vertical distribution and carrier frequency, and preference for open spaces in arboreal katydids that use extreme ultrasound, in Gorgona, Colombia (Orthoptera: Tettigoniidae)

Abstract

Male Tettigoniidae emit sound to attract conspecific females. The sound is produced by stridulation. During stridulation the forewings open and close, but it is during the closing stroke that the scraper contacts the file teeth to generate the predominant sound components, which are amplified by adjacent wing cells specialized in sound radiation. The sounds usually exceed the sonic boundary and might occur above 40 kHz, reaching extreme ultrasonic frequencies of 150kHz in some species. Here we test the hypothesis that Tettigoniidae species should prefer microhabitats that favour efficient signal transmission, i.e. that there is a relationship of sound frequency with the vertical distribution of the species (from ground to canopy) at Gorgona National Natural Park, Colombia. We sampled 16 trees and four different altitudinal levels between 1 and 20m above the understory vegetation. We placed collecting blankets separated by vertical distances of 5m, and knocked insects down using the technique known as fogging. We found no correlation between vertical distribution and carrier frequency, but there was a preference for open spaces (below the canopy and above the understory) in species using extreme ultrasound. This is the first quantitative description of the vertical distribution in neotropical species of the family Tettigoniidae and its relationship to the calling song frequency. Rev. Biol. Trop. 62 (Suppl. 1): 289-296. Epub 2014 February 01.

Satellite remote sensing of environmental variables can predict acoustic activity of an orthopteran assemblage

“…In addition, we explored the relationship of acoustic activity of each species with environmental variables extracted from satellite remote sensing data. We experienced difficulties in collecting canopy dwellers, for which we recommend the use of specialized methods such as fogging ( Montealegre-Z et al, 2014 ), light trapping ( e.g ., Symes et al, 2021 ), or specialized manual tracking ( Diwakar & Balakrishnan, 2007b ) for future studies. As studies on environmental effects on insect acoustic communities are still rare, our study is an important precedent, and serves as a good example on how satellite remote sensing data can be used along with acoustic monitoring schemes in areas with low accessibility to ground-based methods of environmental measurement, such as weather stations.…”

Sheep in wolves’ clothing: prey rely on proactive defences when predator and non-predator cues are similar

“…In a 2-year study of the diet of a gleaning bat species in Panama, Belwood [52] found that C. wheeleri formed the largest proportion of katydids in the diet (23%). Pseudophylline katydids are the most common subfamily of katydid found in gleaning bat diets [28,33,52] and often inhabit the forest understorey (less than 10 m [71]), a common hunting location for eavesdropping bats [72,73]. For these reasons, pseudophylline katydid species might be more likely to respond to the calls of bats than phaneropterine katydids, even if the calls do not correlate well with danger.…”

Ear pinnae in a neotropical katydid (Orthoptera: Tettigoniidae) function as ultrasound guides for bat detection

“…Neotropical katydids have evolved sophisticated auditory features as strategies for survival against substrate gleaning bats 61–65 . The habitat of C. gorgonensis is in cluttered vegetation of the tropical forest understory 66 . In this environment, acoustic signals are heavily attenuated which leads to significant transmission loss 41,67 , but insects have evolved sophisticated receivers to perform call discrimination in these acoustically challenging environments 68 .…”

“…Neotropical katydids have evolved sophisticated auditory features as strategies for survival against substrate gleaning bats (Belwood, 1990;Belwood and Morris, 1987;Nickle and Castner, 1995;ter Hofstede et al, 2017ter Hofstede et al, , 2010. The habitat of C. gorgonensis is in cluttered vegetation of the tropical forest understory (Montealegre-Z et al, 2014). In this environment, acoustic signals are heavily attenuated which leads to significant transmission loss (Rheinlaender and Römer, 1986;Wiley and Richards, 1978).…”