Responses of two parasitoid wasps to nectar odors as a function of experience

Abstract

Adult parasitoid wasps can learn to recognize specific resource‐based cues, making them adept at locating essential resources within their native habitats. However, relatively little is known about their ability to recognize the odors emitted by flowers and extra‐floral nectar glands. A novel test arena mimicking the distribution of nectaries within an umbelliferous inflorescence was developed to measure and compare the responses of two eulophid wasps, Edovum puttleri and Pediobius foveolatus, to nectar‐based odors. Although both parasitoid species were able to associate nectar location with the odors emitted by both real nectaries (dill flowers and snap bean stipules) and artificial nectars (1 M sucrose solution scented with banana or lemon food flavoring), the responses of inexperienced wasps to nectary odors differed. While inexperienced E. puttleri displayed little attraction to the odor of either dill flowers or snap bean stipules, inexperienced P. foveolatus displayed a strong attraction to odors of both types of nectaries. However, once it had experienced foraging on either dill or snap bean nectar, E. puttleri responded to those nectary odors as strongly as did P. foveolatus. The responsiveness of both wasp species to the odor of artificial nectar greatly increased after they foraged on sugar solution scented with either banana or lemon odor. That parasitoid wasp species can differ in their ability to recognize food‐based cues is of fundamental and applied importance.

The Sweet Tooth of Adult Parasitoid Cotesia rubecula: Ignoring Hosts for Nectar?

“…This is less than 10% of the time she needs to ingest a full nectar meal on a honey source with similar sugar concentration (Siekmann et al, 2001). The time needed to gain experience is in the same order of magnitude as published elsewhere (Lewis and Takasu, 1990;Lewis, 1993, 1996;Patt et al, 1999). Straight after the brief feeding experience, wasps experienced the scent of the flowers for an additional 20 s. This was achieved by holding the wasp close to the flowers without allowing her to climb onto them.…”

“…Parasitic wasps use olfaction to locate nectar sources (Leius, 1967;Lewis and Takasu, 1990;Wäckers and Lewis, 1994;Patt et al, 1999) and to some degree visual cues (Wäckers, 1994). There are only a few studies on how parasitic wasps locate potential nectar sources in the presence of hosts.…”

Why Are Some Floral Nectars Scented?

“…However, Patt et al (1999) demonstrated that eulophid parasitoid wasps learn to find and feed from artificial flowers more effectively when they include honey water or Foeniculum nectar than when sugar solutions are used, providing behavioral data suggestive of nectar scent in this system. The sampling methodology was suitable for strongly scented flowers with tubular corollas or spurs and large nectar volumes.…”

Temporal changes in floral nectar production, reabsorption, and composition associated with dichogamy in annual caraway (Carum carvi; Apiaceae)

“…The gradient in solute concentration occurring within a nectar drop (Heracleum mantegazzianum; Corbet et al, 1979) may play an important role in these events. Recently, two species of parasitoid wasps have been shown to respond to odors from nectaries of dill (Patt, Hamilton, and Lashomb, 1999). Although nectaries of the Apiaceae themselves may exhibit distinctive colors (Behrens, 1879), unlike caraway the nectaries even may change hue with floret phenology, as in Anethum graveolens (Szujkó-Lacza, 1971).…”