Response to host plant odors and aggregation pheromone by larvae of the Colorado potato beetle on a servosphere

Abstract

Using a servosphere (locomotion compensator), locomotory behavior of Colorado potato beetle Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae) larvae was measured in detail in response to pulsed and non-pulsed odors of hostplant and conspecific pheromone. Second instars showed decreased straightness of movement, and all larvae showed decreased speed, in response to potato odor. Change in straightness by 2nd instars was also significantly affected by the interaction of pheromone and pulsing treatments. Fourth instars showed increased positive anemotaxis in response to the combined hostplant and pheromone odors. To our knowledge, this is the first demonstration of larval behavioral responses to adult pheromone in a holometabolous insect.

Pulsed Odors from Maize or Spinach Elicit Orientation in European Corn Borer Neonate Larvae

“…While flying insects may need to adopt an active searching strategy to cope with the erratic nature of odorant stimuli in the open air, larvae that are already on their host plants or on their food (Gerber and Stocker 2007) remain confined to the boundary layer of their plant, and may not need to care about the temporal structure of the stimulus. Actually, ECB larvae do not seem to improve their orientation with pulsed stimuli as compared to Colorado potato beetle larvae, which better orient towards intermittent stimuli (1:1 sec pulses) than to a continuous odor (Hammock et al 2007). Our observations merely show that they are capable of taking into account discrete odor stimuli over a large range of pulsing rates and of modulating their search strategy accordingly.…”

“…b Straigthness. c Upward length ( insects, intermitted stimuli improve orientation in carrion beetles (Böhm 1995) and Colorado potato beetle larvae (Hammock et al 2007) but have no effect in others, such as haematophagous bugs that orient towards pulsed CO 2 (Barrozo and Lazzari 2006) or possibly Lobesia botrana larvae, which stop and search for odor cues upon cessation of the stimulus (Becher and Guerin 2009). While flying insects may need to adopt an active searching strategy to cope with the erratic nature of odorant stimuli in the open air, larvae that are already on their host plants or on their food (Gerber and Stocker 2007) remain confined to the boundary layer of their plant, and may not need to care about the temporal structure of the stimulus.…”

“…However, one would expect such odors to induce an arrestment and a local search, rather than a reversal of the direction of orientation. Further studies are needed to clarify these hypotheses, for example, by redesigning the odor delivery system (using a continuous flow over the plant), by sampling and analyzing odors released in different pulsing conditions, by correlating more precisely the timing of the odor stimulation with the behavior of the larvae (as in Hammock et al 2007), or by All factors and binary interactions significantly contributed to the displacement variables (P<0.001 for F values) with the exception of the stimulus flow whose contribution to Upward length was much weaker (* P=0.047).…”

“…We also delivered odors at different pulsing regimes because the temporal structure of the odor plume has been shown to be of special importance to the orientation of adult moths towards pheromone or plant volatiles (Cardé and Willis 2008). Odor pulsing also has been recently reported to influence orientation of larvae of the Colorado potato beetle towards host-plant odors (Hammock et al 2007). Our results demonstrate that ECB larvae showed a slight positive anemotaxis or did not orient to odorless humidified air stream, whatever the pulsing conditions.…”

Multimodal Stimulation of Colorado Potato Beetle Reveals Modulation of Pheromone Response by Yellow Light

“…The male-produced aggregation pheromone ( S )-CPB I elicits electrophysiological responses from olfactory receptors on the antenna of adult CPB and is a potent attractant in dual choice behavioral bioassays under laboratory conditions [18]. This pheromone also elicits attraction of CPB larvae on a servosphere [19]. Additionally, this molecule has been demonstrated to be an effective lure in field tests [20].…”