The ultrastructure of nymphal dermal pores and the genitalia of adult male of Phenacoccus solenopsis (Hemiptera: Pseudococcidae)

The cotton mealybug, Phenacoccus solenopsis, has established itself as an invasive insect pest worldwide. It causes structural and physiological damage to various crops and can cause substantial financial losses in their production. The successful reproduction of this pest under a wide range of conditions is a key to its success. Despite this, the morphology of its genitalia, genital sensilla, and wax-producing dermal pores has received little attention, with little descriptions of their ultrastructure. By investigating those features with SEM, the present study revealed considerable new insights into the identification of the nymphal and adult stages of P. solenopsis. In addition, the description of the ultrastructural genital morphology of the immature stages of P. solenopsis has revealed characteristics that facilitate their discrimination. Trilocular pores were observed on both sides of the body, while the quinquelocular pores were distributed only on the ventral surface in both the first and second nymphal instars. The adult male is characterized by two pairs of waxy caudal filaments surrounded by clusters of 55 to 60 stellate pores, and each pregenital segment bears a pair of stellate pores composed of 4 or 5 peripheral loculi. Sensilla trichodea and numerous microtrichia are present on the pregenital segments. The penile sheath bears three subtypes of sensilla basiconica and also campaniformia, whereas the style bears three subtypes of sensilla campaniformia. The findings of this study could assist in the identification of the adult and nymphal stages of P. solenopsis, and also provide insights into the structures found on the genitalia of the adult male that possibly have an important role in mating events and copulatory behavior. Furthermore, these findings were able to contribute to better understanding the functional morphology of P. solenopsis.

The mouthparts and sensilla of the adult tomato leafminer moth, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae)

In this study, investigation of the morphology and distribution of mouthpart sensilla in the adult tomato leafminer moth, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), using a scanning electron microscope (SEM) is performed. SEM studies examining the mouthparts of Gelechiidae have been noted to be rare; moreover, there have been few investigations on the sensory structures of adult T. absoluta, despite the fact that it is an important pest. In adult T. absoluta, mouthpart structures include the labrum, maxillae comprising two maxillary galeae that form a proboscis, two maxillary palps, and two labial palps. Mandibles were not observed in all studied specimens (30 adults). The proboscis resembles that in other lepidopterous insects and is 1.48 ± 0.08 mm long. Its outer surface is covered with lamellar scales, dense microtrichia, and four sensillum types, that are, aporous sensilla chaetica, uniporous sensilla chaetica, uniporous sensilla styloconica, and aporous sensilla squamiformia. Uniporous sensilla basiconica were also found on the internal face of the proboscis. The labial palps are three-segmented and are known to bear three types of sensilla: squamiformia (present on all three segments), campaniformia, and coeloconica. In this study, we focus on the functional importance of the morphology and distribution of sensilla campaniformia on these labial palps.

Fine Structure of Maxillary Palps in Adults of Hermetia illucens (Diptera: Stratiomyidae)

A relevant species in waste management but also in forensic, medical, and veterinary sciences is the black soldier fly, Hermetia illucens (Linnaeus; Diptera: Stratiomyidae). An ultrastructural study by scanning electron microscopy (SEM) was conducted for the first time on maxillary palps of both sexes, describing in detail the morphology and distribution of sensilla and microtrichia. The maxillary palps, composed of two segments, show sexual dimorphism in length and shape. In both sexes, the first segment is covered only by microtrichia, but the second one is divided into two parts: the proximal one, covered only by microtrichia, and the distal one containing both microtrichia and sensory structures. These structures include two types of sensory pits and one of chaetic sensilla. Due to sexual dimorphism in palp size, females have a higher number of sensory pits. The sexual dimorphism of palps and the presence and role of sensilla in H. illucens was discussed in comparison to other species of the family Stratiomyidae and of other Diptera. This study may represent a base for further investigations on mouthpart structures of this species, involved in key physiological activities, such as feeding, mating and oviposition.

Scanning Electron Microscopy Reveals the Antennal Micromorphology of Lamprodila (Palmar) festiva (Coleoptera: Buprestidae), an Invasive Pest of Ornamental Cupressaceae in Western Palaearctic

Simple Summary

The jewel-beetles, Buprestidae, comprise some economically important invasive pest species. The Cypress jewel beetle, Lamprodila (Palmar) festivafestiva (Linnaeus, 1767), is a new invasive pest of ornamental Cupressaceae, which has recently expanded its range from the Mediterranean region northwards to central and eastern Europe, and to the Russian Black Sea coast. In this study, we used scanning electron microscopy to examine the morphology, numbers, distribution and possible functions of antennal sensilla in both sexes of L. festiva. In total, we identified 15 different (sub)types of sensilla, of which two are present only in females. We discuss possible functions of all examined sensilla and compare them with those in other Buprestidae or other insects. Our study should serve as background information for subsequent chemical ecology research focused mainly on the olfactory sensory system of this rapidly spreading invasive pest.

Abstract

The Cypress jewel beetle, Lamprodila (Palmar) festiva festiva (Linnaeus, 1767), is a serious invasive pest of ornamental Cupressaceae, which has recently expanded its range from the Mediterranean region northwards to central and eastern Europe, and to the Russian Black Sea coast. In this study, we conducted a scanning electron microscopy study of the micromorphology of the male and female antennae of L. festiva to examine the morphology, numbers, distribution, and possible functions of antennal sensilla. Most sensilla are located in the sensory fields within the apical depressions on antennomeres IV–XI. We identified four main types of antennal sensilla in L. festiva: sensilla chaetica (seven subtypes, of which two occur only in females), sensilla basiconica (five subtypes), multiporous grooved pegs (two subtypes), and Böhm sensilla. Females have relatively more sensilla chaetica and multiporous grooved pegs, whereas males have more sensilla basiconica. We discuss possible functions of all examined sensilla and compare them with those in other Buprestidae or other insects. Our study should serve as background information for advanced electrophysiological and behavioral experiments to better understand the functions of different sensilla and mechanisms related to semiochemically based pest control strategies.

Comparative Antennal Morphology of Agriotes (Coleoptera: Elateridae), with Special Reference to the Typology and Possible Functions of Sensilla

Species of the click-beetle genus Agriotes Eschscholtz are economically important crop pests distributed mainly in the Northern Hemisphere. They can inflict considerable damage on various field crops. Therefore, the detection, monitoring, and control of Agriotes include the adult trapping using species-specific sex pheromones, which is a critical component of pest research. To obtain a better understanding of the detailed antennal morphology as background information for subsequent chemical ecology research, we conducted a scanning electron microscopy study of the antennal sensilla of both sexes in 10 European Agriotes species. We identified 16 different sensilla in Agriotes, belonging to six main types: sensilla chaetica (subtypes C1 and C2), sensilla trichodea, sensilla basiconica (subtypes B1–B9), dome-shaped sensilla (subtypes D1 and D2), sensilla campaniformia, and Böhm sensilla. We discuss their possible functions and compare the sensilla of Agriotes with those of other Elateridae in order to consolidate the sensillum nomenclature in this family. Additionally, our study reveals the remarkable interspecific variability in sensillar equipment of Agriotes and identifies several characters of potential importance for future use in systematic studies. The present study provides a strong preliminary framework for subsequent research on the antennal morphology of this crop pest on a wider scale.

Myiasis in domestic cats: a global review

Myiasis is an infestation caused by larvae of Diptera in humans and other vertebrates. In domestic cats, Felis silvestris catus L. (Carnivora: Felidae), four dipteran families have been reported as agents of obligatory and facultative myiasis: Oestridae, Calliphoridae, Sarcophagidae and Muscidae. Among agents of obligatory myiasis, the most frequent genus is Cuterebra Clark (Oestridae) and the most frequent species is Cochliomyia hominivorax (Coquerel) (Calliphoridae). Among the agents of facultative myiasis, the most frequent species is Lucilia sericata (Meigen) (Calliphoridae). A survey of myiasis in cats reported in literature shows that the cases are distributed worldwide and linked to the geographical range of the dipteran species. Factors favouring the occurrence of myiasis in cats are prowling in infested areas, poor hygiene conditions due to diseases and/or neglect, and wounds inflicted during territorial or reproductive competition. The aim of the review is to provide an extended survey of literature on myiasis in cats, as general information and possible development of guidelines for veterinarians, entomologists and other researchers interested in the field.

Morphology and distribution of antennal sensilla in the female and male clothes moth, Tineola bisselliella Humm. (Lepidoptera: Tineidae)

We have examined antennae of both sexes of Tineola bisselliella to make an inventory of the antennal sensilla. We distinguished two types of sensilla trichodea, two types of sensilla basiconica, and sensilla auricillica, chaetica, coeloconica, styloconica, and campaniformia, Böhm's bristles, and squamiform structures. The same types of sensilla are present in both sexes. Numbers of sensilla chaetica, styloconica, and coeloconica and Böhm's bristles do not differ between the sexes. Significant differences in number and distribution of sensilla trichodea, basiconica, and auricillica were found between females and males over the whole length of the antenna.