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

Abstract

Female parasitoids are guided by multisensory information, including chemical and physical cues during host location. In the present study, we investigated the behavioural responses of naïve Fopius arisanus (Sonan) females to visual targets baited with guava odour. In non-choice wind tunnel tests, the attraction and landing responses of parasitoids to spheres painted with different colours, and targets of different shapes and sizes were evaluated. Females were more frequently attracted and landed more often on dark yellow targets than on targets with other colours. There was no correlation between the brightness of each colour and the attraction or landing responses. In contrast, both responses were correlated with relative reflectance (hue) of the coloured targets. A positive correlation was observed between attraction and hue, and a negative correlation between landing and hue. F. arisanus was attracted to and landed more often on spheres than on other shape models. The attraction response of this parasitoid was affected by the size of the targets, with spheres of 10 and 12 cm diameter being more attractive than spheres of 8, 6 and 4 cm diameter. The fact that F. arisanus females were able to discriminate among visual targets that differ in colour, shape and size stresses the importance of vision during host location by this species.

Chemical Cues Induced from Fly-Oviposition Mediate the Host-Seeking Behaviour of Fopius arisanus (Hymenoptera: Braconidae), an Effective Egg Parasitoid of Bactrocera dorsalis (Diptera: Tephritidae), within a Tritrophic Context

“…However, almost all of the above-mentioned studies exposed entire fruits to F. arisanus, making it difficult to discriminate whether the effect on host location behaviour was a result of the shape, size, and colour of the fruit, an odour, or a combination of these cues. Furthermore, visual information is often important in host location for parasitoids [20]; Fopius arisanus females are significantly more attracted to and landed on objects that were dark yellow rather than objects of other colours [31].…”

The effectiveness of two types of adhesive for catching insects in traps

“…The situation differed on yellow card traps where HMPSA was superior to PBA. Many insects including Hymenoptera have a strong attraction to yellow colours (Perez et al 2012). The yellow card traps with PBA were a similar, but not identical, shade of colour to those with HMPSA and this may have influenced the greater attraction to the latter.…”

An improved culturing method for opiine fruit fly parasitoids and its application to parasitoid monitoring in the field

“…We suspect the extremely low parasitism in Petri dishes might have resulted from disruption to pre‐ and postalighting behaviors that insects use to find their hosts (Kennedy, ) through the absence of important sensory cues. Host fruit shape is likely to be an important factor, as has been shown in other fruit fly parasitoids (Perez et al ., ): our culturing bags may be providing important visual cues that increase female alighting on the infested media and trigger their search for larvae. The location of the culturing bag (i.e., hanging compared to the Petri dish on the floor of the cage) could also have played a role in increasing oviposition (although it should be noted that the nectarine was placed on the floor of the cage), and suspending the nectarines (and Petri dishes) could have increased parasitism rates.…”