Musculature of the male genitalia of Xylophagus cinctus (De Geer) and relationships within the superfamily Xylophagoidea (Diptera, Brachycera)

There is no general agreement on relationships within Xylophagoidea (Diptera, Brachycera). The musculature of the male genitalia of Xylophagus cinctus (De Geer) (Xylophagidae, the most primitive family of Brachycera) is described and compared with that of some other Xylophagoidea: Exeretonevridae (Exeretonevra angustifrons Hardy), Coenomyiidae (Anacanthaspis biafasciata Röder), and Rhagionidae (Rhagio montanus Becker, Chrysopilus dives Loew, and Ch. helvolus Meigen) discussed earlier (Ovtshinnikova, 1989, 1998; Palmer et al., 2000). In spite of the differences in the structure of the genital sclerites, Xylophagidae possess all the muscles found in Coenomyiidae and Rhagionidae. The musculature of the male genitalia of Xylophagus cinctus includes two muscle pairs of the aedeagus sheath (M1 and M2); three muscle pairs of the ejaculatory complex (M30, M31, and M32); one muscle pair of the gonocoxites (M33); two muscle pairs of the gonostyli (M27 and M28); one muscle pair of the proctiger (M21), one muscle pair of the cerci (M29); two pairs of the tergosternal muscles (M5 ¹ and M5 ²); and two pairs of the pregenital muscles (M18 and M19). Muscles of the family Exeretonevridae are mostly the same, except for the muscles of the cerci M29, proctiger M29, and pregenital muscles M18 and M19, that are subdivided into two parts. This fact and also a different degree of the development of muscles M32 and M5 ² clearly distinguish Exeretonevridae from closely related families. The attachment places of the muscles of the aedeagus sheath M2 and of the gonostyli M28, as well as the split character of the tergosternal muscle pair M5 ¹ makes it possible to distinguish two sister groups, Xylophagidae plus Exeretonevridae, versus Coenomyiidae plus Rhagionidae. It should be noted that the muscles of the male genitalia of Xylophagidae, Exeretonevridae, Coenomyiidae, and Rhagionidae possess similar plesiomorphic characters, and these families should be united into the superfamily Xylophagoidea. This superfamily is the most primitive superfamily of Brachycera Orthorrhapha and possesses the most stable set and arrangement of male genital muscles within the entire suborder. An improved dendrogram of the phylogenetic relationships between the known groups of Xylophagoidea is proposed on the basis of the structure of male genital muscles.     

Resource density regulates the foraging investment in higher termite species

1. Resource density can regulate the area that animals use. At low resource density, there is a conflict in terms of balance between costs of foraging and benefits acquired. The foraging of the higher termite Nasutitermes aff. coxipoensis consists of searching throughout trails and a building galleries phase. 2. In this study, a manipulative field experiment was used to test the hypothesis that colonies of N. aff. coxipoensis forage towards a more profitable balance between the establishment of trails and gallery construction at low resource density. 3. The experiment was conducted in north‐eastern Brazil. Seven experimental plots were established with a continuous increase in resource density (sugarcane baits). Entire colonies of N. aff. coxipoensis were transplanted from their original sites to the experimental plot, totalling 35 nests. The number, branches and total length of trails and galleries were quantified. 4. The results show that N. aff. coxipoensis optimises its foraging output, intensifying the establishment of trails at the cost of gallery construction when resource density is low. The number of trails, the number of trail branches and the total length of trails decreased with increasing resource density. Interestingly, at low resource density, the search effort was concentrated on forming longer and a greater number of trails, a small proportion of which were converted into galleries. The opposite relationship was observed at high resource density. 5. These results suggest an optimisation of search efforts during foraging depending on resource density, a mechanism that may help researchers to understand the use of space by higher termite species.     

The ovipositor musculature of Carpomya schineri (Loew) (Diptera, Tephritidae)

The structure of the ovipositor sclerites and musculature was studied in the tephritid fly Carpomya schineri (Loew) whose larvae develop in the fruits of Rosa. The structural characters of the ovipositor of this species facilitating laying eggs into such fruits are discussed. The ovipositor musculature and functioning in Carpomya are very similar to those in Ceratitis and Bactrocera; species of all these genera lay eggs in fruits. In the details of the ovipositor musculature, Carpomya is more similar to Ceratitis than to Bactrocera. The genera Carpomya, Ceratitis and Bactrocera are phylogenetically close but Ceratitis and Bactrocera belong to sister tribes within one subfamily, Dacinae. Thus, morpho-functional similarity of the ovipositor structure may not only reflect close relationship but also result from common adaptive transformations.     

Musculature of the ovipositor of <Emphasis Type="Italic">Oxyna parietina</Emphasis> (Linnaeus, 1758) (Diptera,Tephritidae) and its relation to the larval habits

The structure of the ovipositor sclerites and muscles was studied in the tephritid fly Oxyna parietina (Linnaeus, 1758) inducing galls on the stems of Artemisia vulgaris. Adaptations of the ovipositor structure associated with changes of the oviposition substrate due to new larval habits are analyzed. The ovipositor muscles of Oxyna parietina are compared to those of Campiglossa. The genera Oxyna Robineau-Desvoidy, 1830 and Campiglossa Rondani, 1870 belong to the same genus-group of Tephritini, but differ in their host associations and oviposition habits: the larvae of Campiglossa plantaginis (Haliday, 1833) develop in the capitula of Aster tripolium and other asters (Asteraceae). The ovipositor sclerites and muscles are similar in the two genera. Progression of hemolymph into the membranous sheath of the ovipositor and protraction of the aculeus are necessary conditions for laying eggs into the capitula of Asteraceae (Campiglossa plantaginis), as well as for insertion of eggs into the axils of Artemisia leaves (Oxyna parietina). The most significant characters of Oxyna and Campiglossa include the presence of the hyaline apodeme and associated muscles MVM 6 and MVM 7 (instead of the median apodeme in Urophora). Thus, in other tephritid flies similarity in the structure of the ovipositor muscles may reflect similar morphofunctional adaptations to laying eggs into similar substrates, but similarity of Campiglossa and Oxyna in the structure of the ovipositor muscles is due to their close relations.     

The male abdominal,genital and pregenital sclerites and musculature in <Emphasis Type="Italic">Neria commutata</Emphasis> (Czerny, 1930) (Diptera,Micropezidae)

The muscles of the male abdomen and genitalia of Micropezidae were studied for the first time by the example of Neria commutata (Czerny, 1930). Based on analysis of the sclerites and musculature of the male genitalia of Micropezidae as compared to those of the previously studied Acalyptratae and Aschiza, we revealed several apomorphies of this group. The hypandrial complex is characterized by the presence of the phallic retractors and protractors M1 and M2, and the epandrial complex, by the presence of muscles M3 of the subepandrial sclerite, muscles M4 of the surstyli, muscles M7 of the cerci, and also the tergosternal muscles M5; all these muscles correspond to the ground plan of Cyclorrhapha. The following characters are considered apomorphic: the splitting of intersegmental sternal muscles ISM5–6 into 4 pairs that ensure the functioning of the forcipate appendages of sternite V; development of syntergosternite VII and reduction of muscles ISM6–7; the splitting of muscles M3 of the subepandrial sclerite into 4 pairs, enhancing the function of this sclerite; the appearance of pregonites with the associated muscles M42, which probably occurred independently several times in the evolution of different groups of Cyclorrhapha; asymmetry of syntergosternites VII and VIII and their muscles. The sclerites and muscles of the epandrium and hypandrium are characterized by complete symmetry.     

The Skeleton and Musculature of the Male Genitalia in Platypezidae (Diptera)

Entomological Review - The musculature of the male genitalia of Platypezidae (Diptera) is described for the first time. The hypandrium in members of the subfamilies Platypezinae and Callomyiinae...     

Skeleton and musculature of the male genitalia in the family Nothybidae (Diptera)

Sclerites and musculature of the male genitalia of Nothybidae (Diptera) were studied for the first time. Symmetry of the genital and pregenital sclerites, similar to that in Psilidae, was revealed. The muscles of the male genitalia of Nothybus resemble the apomorphic plan of Cyclorrhapha (Sciomyzidae, Scathophagidae and Calliphoridae) due to the splitting of the hypandrium and hypandrial muscles.     

Musculature of the Male Abdominal Segments and Terminalia of Mydaea urbana (Meigen, 1826) and Graphomya maculata (Scopoli, 1763) (Diptera,Muscidae: Mydaeinae)

Entomological Review - The structure of the abdominal and pregenital segments and genitalia was studied in males of Mydaea urbana (Meigen, 1826) and Graphomya maculata (Scopoli, 1763) (Muscidae,...