Anemotactic orientation of gypsy moth males and its modification by the attractant pheromone (+)‐disparlure during walking

Abstract

Tracks of dewinged gypsy moth males, Lymantria dispar L. (Lymantriidae), walking upwind in an airstream without pheromone consist of marked alternations between more or less straight upwind segments, partly with an arcadic structure, and twisted segments. This apparently complicated behaviour can, however, simply be explained by a superposition of noise and two turning commands: an upwind turning tendency, derived from the anemoreceptive system, which represents an average of the moth's angular positions over a period of time; and an internal turning tendency which consists of strong but brief bursts. These bursts are produced intermittently; successive bursts do not necessarily alternate polarity. Amputation of one antenna increases the probability of bursts towards the amputated side; therefore a separate burst source is postulated for each antenna. In the presence of the attractant pheromone (+)disparlure, the anemotactic signal is weighted higher; twisted segments are, therefore, less pronounced.There is a chemotropotactical component involved in the male's orientation. The tropotactical signal, dependent on the difference of odour concentration perceived by the left and right antenna, competes with the upwind turning tendency.

Prolonged effects of the insecticide dimethoate on locomotor behaviour in the woodlouse, Porcellio scaber Latr. (isopoda)

“…Detailed quantitative studies of locomotor patterns in invertebrates are rare, most of the existing work being carried out with the locomotor compensator (Kramer 1976). Whilst this apparatus is ideally suited to quantifying the responses of small animals to odours (Kramer 1976;Preiss and Kramer 1986;Thiery and Visser 1986), to wind direction (Heinzel and B6hm 1989) and to humidity (Sorensen and Bell 1986), it does not permit the animal to walk on various substrates including contaminated soil.…”

Antennal mechanosensors mediate sex pheromone‐induced upwind orientation in the potato tuberworm moth

“…Normal upwind flight with unaffected accuracies of upwind surges is shown for single‐antenna Heliothis virescens males (Vickers & Baker, ) and successful location of pheromone sources is shown to be unaffected in single‐antenna Plodia interpunctella males (Kennedy & Marsh, ). Unilaterally antennectomized walking Lymantria dispar males stimulated by pheromone are also able to orient upwind accurately without the possibility of using tropochemotaxis (Preiss & Kramer, ).…”

“…To date, the reported functions of antennal mechanosensory organs in lepidopterans are limited to flight controls when airborne (in the small tortoiseshell Aglais urticae : Gewecke & Niehaus, ; Niehaus, ; in M. sexta : Sane et al , ; Hinterwirth & Daniel, ). Some studies demonstrate that males of several moth species that normally perform sustained upwind flight in response to pheromone are also able to orient upwind when walking (Preiss & Kramer, ; Willis & Baker, ; Willis et al , ; Minoli et al , ; Party et al , ). In the corn earworm Helcoverpa zea , the take‐off orientation is directed upwind (Crespo et al , ), suggesting that detection of wind direction is made pre‐flight via mechanoreception when the males are still on the ground.…”

Odour‐conditioned anemotaxis of apterous aphids (Cryptomyzus korschelti) in response to host plants

“…This principle was statistically verified, for the beetles as well as the aphids, by calculating correlation coefficients between variables (Visser & Thiery, 1987). An analogous description was followed by Preiss & Kramer (1986) for the anemotactic orientation of gypsy moth males towards a source of sex pheromone.…”