Perception of Chromatic Cues During Host Location by the Pupal ParasitoidPimpla turionellae(L.) (Hymenoptera: Ichneumonidae)

Abstract

Chromatic and achromatic plant cues are expected to be particularly important for parasitoids of endophytic pupal hosts, because these stages do not feed and therefore avoid volatile emission caused by plant tissue damage. Endophytic feeding can cause discoloration or desiccation, leading to changes in color and/or brightness of infested plant parts that may be visually detected by parasitoids. The role of color cues in the host-Þnding behavior of parasitoids is poorly understood, and the visual system of most parasitoid species has not yet been investigated. We studied color discrimination ability and innate color preferences in the pupal parasitoid Pimpla turionellae (L.) (Hymenoptera: Ichneumonidae) during location of concealed hosts. Responses to combinations of yellow and blue bands of different reßectance intensities were investigated on cylindrical models of plant stems. The parasitoidÕs reaction to these chromatic cues was evaluated by scoring the number of ovipositor insertions into the colored bands. Female parasitoids discriminated blue from yellow irrespective of total reßectance and inserted their ovipositors signiÞcantly more often into the blue area. True color vision is demonstrated for the examined species, and responses to chromatic cues are discussed in relation to their importance for host location in parasitoids. Results of this study and of our previous work suggest that P. turionellae uses contrasts (chromatic or achromatic) rather than speciÞc color characteristics in visual host location.

Olfactory versus Contact Cues in Host Plant Recognition of a Monophagous Chrysomelid Beetle

“…To find and identify their host plants, insects could use various sensory systems. A combination of visual (Bullas-Appleton et al, 2004;Fischer et al, 2004;Hausmann et al, 2004;Mäntylä et al, 2004), olfactory (Müller & Hilker, 2000;Kalberer et al, 2001;Zhang & Schlyter, 2004;Kalberer et al, 2005), and contact or gustatory cues (Jermy et al, 1988;Chapman & Sword, 1993;Mitchell, 1994;Schoonhoven et al, 1998) can finally lead the insect to its food source. However, all these cues vary in both their cost of assessment and accuracy, and some cues can be more reliable than others (Fawcett & Johnstone, 2003).…”

Host plant finding in the specialised leaf beetle Cassida canaliculata: an analysis of small‐scale movement behaviour

“…However, this similarity in shape may only appear to the human eye and not to the beetles, as they may even be able to use the spectral composition of the plant tissue for host plant recognition (Bullas-Appleton et al, 2004;Fischer et al, 2004;Mäntylä et al, 2004). Furthermore, the beetles may use a combination of olfactory and visual cues, which has also been found in other herbivorous insects (McIntyre & Vaughn, 1997;Cook & Neal, 1999;Strom et al, 1999;Barata & Araújo, 2001;Szentesi et al, 2002).…”

Vision-mediated exploitation of a novel host plant by a tephritid fruit fly

“…cucurbitae has revealed that females are particularly attracted to pigments that offer high reflectance values (white, yellow, orange) regardless of hue and, conversely, that they respond less to objects associated with low-reflecting pigments (e.g., black, blue) [26]. Some parasitoid species uses contrast (chromatic or achromatic) rather than specific color characteristics in visual host location [39]. Our findings demonstrate that visual acuity may have mediated the establishment of new host / plant relationships, ahead of olfactory adaptations.…”