# The Olfactory System of Dolichogenidea gelechiidivoris (Marsh) (Hymenoptera: Braconidae), a Natural Enemy of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

## TL;DR

This study explores how male and female wasps of Dolichogenidea gelechiidivoris use their sense of smell differently, which could help in controlling the invasive pest Tuta absoluta.

## Contribution

The study reveals sex-specific olfactory differentiation through morphological and molecular analyses in a parasitoid wasp.

## Key findings

- Males have significantly longer antennae than females, showing sexual dimorphism.
- Transcriptomic analysis identified 11 OBPs and 20 ORs, with sex-specific gene expression patterns.
- Sex-specific olfactory specialization may influence the use of volatile cues for biological control.

## Abstract

The parasitoid wasp Dolichogenidea gelechiidivoris is a key koinobiont solitary endoparasitoid of the invasive agricultural pest Tuta absoluta. This study investigates both the morphological and molecular foundations of sex-specific olfactory differentiation in this species. Morphological analysis revealed that males possess significantly longer antennae (2880.8 ± 20.36 μm) than females (2137.23 ± 43.47 μm), demonstrating pronounced sexual dimorphism. Scanning electron microscopy identified similar sensilla types on both sexes, but differences existed in the length and diameter of specific sensilla. Transcriptomic analysis of adult antennae uncovered molecular differentiation, identifying 11 odorant-binding proteins (OBPs) and 20 odorant receptors (ORs), with 27 chemosensory genes upregulated in females and 4 enriched in males. Integrating morphological and molecular evidence demonstrates complementary sexual specialization in the olfactory apparatus of D. gelechiidivoris. Linking these findings to the potential functions of different sensilla types, as discussed in the context of prior research, provides crucial insights into the sex-specific use of volatile cues. These findings provide critical insights into the use of volatile signals in this highly relevant species for biological control targeting T. absoluta.