Morphology of putative female sex pheromone glands and mating behaviour in Aphidoletes aphidimyza

Abstract

Adult emergence period, sex ratio, female calling behaviour, and the risky mating behaviour of A. aphidimyza in spider webs are described. We provide evidence that A. aphidimyza females produce a sex pheromone and attract males, and we give a description of the location and structure of the supposed pheromone producing glands of A. aphidimyza based on scanning and transmission electron microscopy. This is the first demonstration of occurrence of sex pheromones for a zoophagous species of Cecidomyiidae. The question is discussed why A. aphidimyza is using spider webs for mating.

Female sex pheromone gland of the boxwood leafminer, Monarthropalpus buxi (Diptera: Cecidomyiidae): Morphological and behavioural evidence

“…In this type of glandular cell, the secretions simply pass through the overlying cuticle via pore canals and there are no other structures associated with the accessory cells. This appears to be a common feature of the pheromone glands of gall midges, as currently there is no evidence of glandular epithelia with secretory cells that are typical of other types of gland cells (Solinas & Isidoro, 1991Isidoro et al, 1992;van Lenteren et al, 2002). In addition, there are several other ultra-structural features of the secretory cells, such as a well-developed smooth endoplasmic reticulum (SER) that is widespread throughout the cytoplasm and Golgi complexes.…”

“…The existence of a sex pheromone gland is documented currently for only four species of gall midges, three phytophagous (Solinas & Isidoro, 1991Isidoro et al, 1992) and one zoophagous species (van Lenteren et al, 2002). In all of these species, the females have a soft, tapered, telescopic and flexible ovipositor, which is made up of the last three abdominal segments (the 8 th , 9 th and 10 th uromeres) and the sex pheromone gland of the female is located in the epidermis of the inter-segmental membrane that connects the 8 th and 9 th abdominal segments.…”

“…In M. buxi, the glandular tissue is located below the inter-segmental cuticle between the 8 th and 9 th uromeres, which is similar to the basic pattern found in Contarinia sorghicola (Coquillett) (Solinas & Isidoro, 1991), Dasineura brassicae Winn. (Isidoro et al, 1992), M. destructor (Solinas & Isidoro, 1996), Aphidoletes aphidimyza (Rondani) (van Lenteren et al, 2002), the majority of Lepidoptera (Percy-Cunningham & MacDonald, 1987), Bruchidae (Biémont et al, 1992;Ramaswamy et al, 1995;Pierre et al, 1996) and Staphylinidae (Happ & Happ, 1973). The thickness of the epithelium differs in the few Cecidomyiids studied, which appears to depend on the shape and size of the ovipositor: in C. sorghicola and D. brassicae, the glandular epithelium is very thin, while in M. destructor and A. aphidimyza, it is relatively thick, as in M. buxi.…”

“…The existence of female-produced sex pheromones has been demonstrated for 10 phytophagous species (Harris & Foster, 1999;Hall et al, 2012) and one zoophagous species (van Lenteren et al, 2002). The components of the female sex pheromones of 17 species of gall midges have also been identified and shown to attract conspecific males in field experiments and/or laboratory bioassays (Hall et al, 2012;Fitzpatrick et al, 2013).…”

“…The sex pheromone gland is in the region of the ovipositor. In several species, this consists of the last three abdominal segments (the 8 th , 9 th and 10 th uromeres) (Harris & Foster, 1999), while in four species, these glands are located in the epidermis of the inter-segmental membrane that connects the 8 th and 9 th abdominal segments (Solinas & Isidoro, 1991Isidoro et al, 1992;van Lenteren et al, 2002).…”