Host color preferences and short‐range searching behavior of the egg parasitoid Trichogramma ostriniae

Abstract

The color of lepidopteran eggs often varies by species or egg condition, and parasitoids that attack lepidopteran eggs could therefore potentially use color to obtain information about host identity or quality. The objective of our study was to determine whether females of the egg parasitoid Trichogramma ostriniae Pang & Chen (Hymenoptera: Trichogrammatidae) showed differential responses to egg color when searching for hosts over short distances and when evaluating the suitability of encountered eggs. We examined the wasps' host-selection behavior in a Petri dish arena using white, yellow, green, and black clay beads as egg models presented against a green background (to mimic leaf color). In no-choice tests, bead color had a significant effect on the proportion of tested wasps that accepted a bead for further examination, on the time it took wasps to find and begin examining a bead, and on the time that wasps spent examining the beads. However, bead color had only a marginally significant effect on the proportion of wasps attempting to drill into a bead with their ovipositors, and no significant effect on the amount of time they spent drilling. The wasps also showed significant color preferences when given a choice between two adjacent beads of different colors. The results of the nochoice and choice trials taken together indicated a color preference ranking of yellow > white > green > black. The wasps' higher preference for the yellow and white egg models generally corresponds to the white or yellowish-white egg color of T. ostriniae 's target host, the European corn borer moth, Ostrinia nubilalis Hübner (Lepidoptera: Crambidae). The wasps' strong rejection of black egg models is likely to be an adaptive response that reflects the fact that eggs that are wholly or partially black are often unsuitable for parasitization due to advanced caterpillar development, damage to the egg, or previous parasitization.

Influence of visual cues on host‐searching and learning behaviour of the egg parasitoids Telenomus podisi and Trissolcus basalis

“…For egg parasitoids there is less information related to the use of colours during host searching with the exception of some studies on Trichogramma spp. (Romeis et al, 1998;Lobdell et al, 2005) and for the egg parasitoid Ooencyrtus kuwanai (Howard) (Weseloh, 1972).…”

“…Many phytophagous insects have a preference for particular structures of plants to feed or lay eggs (Udayagiri & Welter, 2000;Blackmer et al, 2001); these structures can be told apart by the parasitoids based on colour, allowing them to select (micro) habitats when foraging. The colour of the host can also help the parasitoids in recognition and in gathering information about host quality (Lobdell et al, 2005). In addition, parasitoids could use colours when foraging for food, to guide themselves towards flowers to find nectar, or other food resources (Wäckers, 1994) Host-searching behaviour of parasitoids is influenced by innate behaviour, experience, and associative learning (Vinson, 1998).…”

Size, shape and hue modulate attraction and landing responses of the braconid parasitoid Fopius arisanus to fruit odour-baited visual targets

“…The preference for the colour yellow we found in F. arisanus has been reported for other hymenopterans, including egg parasitoids (Lobdell et al 2005). In the case of fruit fly parasitoids, Diachasmimorpha juglandis (Muesebeck) chose yellow walnut fruits over black fruits despite that the latter are more likely to contain host larvae (Henneman 1998).…”

Effects of host-plant density on herbivores and their parasitoids: A field experiment with a native perennial legume

“…Parasitoids' color ! 7 preference, however, could be linked to information regarding hosts' identity, developmental stage, substrate, or previous parasitization (Lobdell et al, 2005). In addition, parasitoids' behavior towards stimuli is affected by mechanical cues that evoke further responses.…”

“…Lobdell et al (2005) indicated that the egg parasitoid, Trichogramma ostriniae, using color as a visual cue, has the potential to control the density of the lepidopteran Ostrinia nubilalis in maize fields. The parasitoid's behavior towards yellow, black, white, and green beads representing the eggs was analyzed using a Petri dish arena with green background.…”