Malformations of the genitalia in male Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae)

Phlebotomus papatasi ( Scopoli, 1786 ) (Diptera: Psychodidae) is a major vector of Leishmania major (Kinetoplastida: Trypanosomatidae), a causative agent of zoonotic cutaneous leishmaniasis. Morphological characters of sand fly genitalia are key indicators for species identification. Various anomalies affecting male genitalia have been previously described. We take advantage of a large sand flies survey conducted in 32 stations in Central and Southern Morocco to systematically quantify the prevalence and spatial distribution of malformations affecting the genitalia of P. papatasi. Among 597 examined males, 122 were abnormal (20.4%). Malformations were widespread and largely concerned the number of spines in the lateral lobes and in the styles. Asymmetrical anomalies in lateral lobes were common. Correspondence analysis of our results highlighted the symmetrical anomalies observed in the lateral lobes, and abnormal styles of the male genitalia were found to be associated with environmental disturbances since they were prevalent in sewage dumps.     

What determines the number of ovarioles in a fly ovary?

The relation between the size of a fly and the number of ovarioles in its ovary was investigated in Phormia regina and Sarcophaga bullata. Small flies of varying size were produced by taking larvae prematurely off the food. The smallest flies thus obtained were derived from larvae only $\text{1}\text{8}$ of the weight of a normal larva. The number of ovarioles in an ovary is directly proportional to the size of the fly and, in the extreme case, is about $\text{1}\text{5}$ the normal number in Sarcophaga and about $\text{1}\text{3}$ in Phormia. Larvae prematurely taken off the food, but fed again after starving for several days, grow to normal or almost normal size and develop ovaries with about the normal number of ovarioles. Small or re-fed Sarcophaga do not show any changes in the anatomy of individual ovarioles but in Phormia disorders in ovariole development and a consequent reduction of fertility are frequent. The number of ovarioles remains identical from the early pupal stage all through the development of the pharate fly and then through ovarian development in the adult fly: it is determined by the size of the larva when it was taken off the food. This shows that it is not lack of space in a small adult fly abdomen which determines the number nor the occurrence of degenerative processes during ovarian development.     

Diptera of forensic importance in the Iberian Peninsula: larval identification key

A revision of the species and families of sarcosaprophagous flies (Diptera: Calliphoridae, Sarcophagidae, Muscidae, Fanniidae, Drosophilidae, Phoridae, Piophilidae and Stratiomyidae) suitable for forensic purposes in the Iberian Peninsula is presented. Morphological characteristics that allow the accurate identification of third instars of the species present in the Iberian Peninsula are described and presented in the form of a diagnostic key. For larval Calliphoridae, characteristics such as the spines of the body segments were useful for the genus Calliphora whereas features of the anal segment and the cephalopharyngeal skeleton were useful for larvae of Lucilia. Identification of three Chrysominae species present in the Iberian Peninsula is included. For larval Sarcophagidae, characters such as the arrangement and shape of spiracular openings, structures of the anal segment and the cephalopharyngeal skeleton were used for the first time. A new record of Sarcophaga cultellata Pandellé, from a human corpse, is also included as well as recent incursions into the European cadaveric entomofauna such as Synthesiomyia nudiseta (van der Wulp) and Hermetia illucens (Linnaeus). This work provides useful new information that could be applied to forensic investigations in the Iberian Peninsula and in southern Europe.     

The Function of Hitchhiking Behavior in the Leaf‐cutting Ant Atta cephalotes1

In some leaf‐cutting ant species, minim workers ride on the fragments of leaves as they are carried back to the nest from the cutting site. There is convincing evidence that these “hitchhikers” can protect the leaf carriers from attack by phorid (Diptera: Phoridae) parasitoids, but we consider the possibility of other functions for the hitchhiking behavior. It has been hypothesized that the hitchhikers (1) feed on leaf sap from the edges of the cut leaves; (2) ride back to the nest to save energy; (3) get caught on the fragments as they are cut, and hitchhike because they cannot (or will not) get off; and (4) begin the process of preparing the leaf to enter the fungal gardens in the nest, perhaps by removing microbial contaminants. We observed hitchhikers of Atta cephalotes in 14 nests at the La Selva Biological Station in Costa Rica. There was no difference in the proportion of leaf carriers with hitchhikers between day and night. Because the nests we observed were largely nocturnal, more than 90 percent of the hitchhiking occurred at night. The phorid parasitoids are usually considered to be diurnal, so the preponderance of nocturnal hitchhiking suggests other functions in addition to parasitoid defense. Hitchhikers spent more time in the defensive head‐up posture during the day, but spent more time in the head‐down posture at night. The head‐down posture may indicate cleaning or other leaf preparation. The hitchhikers were never observed feeding on sap. Hitchhikers frequently got onto and off of the fragments, and so they were not “marooned.” Few hitchhikers rode all the way back to the nest and were often moving on the leaf fragment; these observations make the energy conservation hypothesis less likely, although we cannot reject it. We conclude that parasitoid defense is an important function of hitchhiking but also that there are probably other functions when parasitoids are absent. Based on available data, the most likely possibility is preparation of the leaf fragment before it enters the nest.     

Habitat size, flora, and fauna: Interactions in a tidal saltwater marsh

Anthropogenic habitat fragmentation is increasingly problematic in both terrestrial and aquatic systems. Fragmentation reduces the size of habitat patches, so examining the effect of patch size on community structure can provide insight into the potential effects of fragmentation. In this study, we examined the effect of habitat size on the density of Spartina alterniflora shoots in tidal saltwater marshes, as well as on the two predominant macrofaunal species, the marsh periwinkle Littoraria irrorata and fiddler crabs Uca spp. We estimated the density of shoots in three different marsh habitats, (1) large island marshes, (2) small island marshes, and (3) large fringing marshes, in Indian Field Creek, York River, Chesapeake Bay. We manipulated shoot density in each of the marsh types to distinguish between the effects of marsh grass density and marsh type on crab and Littoraria densities in the system. We found significant differences in grass density among the three marsh types as well as significant species-specific effects of grass density, marsh type, and distance from edge on faunal abundance. Decreasing the shoot density resulted in a decrease in Littoraria density in the large marshes. Littoraria density increased with distance from edge in the small marshes and in the first 5 m of the fringing marshes, then decreased with distance from edge after 5 m in the fringing marshes. Shoot density had a negative effect on crabs in both the large and small marshes. These results suggest that fragmentation would have a negative effect on the community structure by lowering the densities of both the flora and fauna.     

The effect of four fruit species on the parasitization rate of Anastrepha fraterculus (Diptera: Tephritidae,Trypetinae) by Diachasmimorpha longicaudata (Hymenoptera: Braconidae,Opiinae) under laboratory rearing conditions

In the laboratory, the effect of host fruit species Citrus paradisi, C. aurantium, Prunus persica, and Psidium guajava on A. fraterculus parasitism by Diachasmimorpha longicaudata was studied. The number of ovipositor-probing events and the probing-time were documented to evaluate the role of fruit chemistry, and epicarp and mesocarp thickness, respectively. The relationship between the parasitization rate and fruit size in particular plant species was analyzed by applying a simple regression. Results showed that guava and peach yielded significantly more parasitoids than both Citrus spp. Probably, the parasitization rate of D. longicaudata on A. fraterculus would be influenced in part by chemical and physical factors from fruit species.     

Dispersion patterns of Diachasmimorpha longicaudata (Hymenoptera: Braconidae) in citrus orchards in southeast Brazil

We studied the dispersion patterns of the exotic endoparasitoid, Diachasmimorpha longicaudata (Ahsmed) (Hymenoptera: Braconidae), in 1999 (summer) and in 2000 (winter) in a citrus orchard in southeast Brazil. Different population densities of D. longicaudata were released in the centre of the orchard, and their dispersion was determined by using yellow, sticky, rectangular traps, placed in various distances and heights around the release point. Our results suggest that during summer, climatic conditions did not affect dispersion. However, in winter, dispersion rates were positively affected by temperature, and negatively by rainfall. Both estimated dispersal distance and surface were higher in summer than in winter for all release densities. Dispersion peaked at 2000 parasitoids ha^?1 in summer and 8000 parasitoids ha^?1 in winter. The importance of our results for the biological control of fruit flies by augmented or innoculative releases of D. longicaudata in southeast Brazil is discussed.     

Spiroplasma species in the Costa Rican highlands: implications for biogeography and biodiversity

More than 1,000 Spiroplasma isolates have been obtained from horse flies and deer flies (Diptera:Tabanidae) in the United States and Canada. However, the spiroplasma biota of Central America is poorly known. In August of 1995 and 1998, 13 isolates were obtained in 14 attempts from horse flies of a single species, Poeciloderas quadripunctatus, taken in the Costa Rican highlands (1,100–2,000 m). The majority of the “isolates” proved to be mixtures of two or more Spiroplasma species, but after filter cloning, single strains emerged that were designated as representatives of the 13 accessions. Six distinct spiroplasma serogroups were identified from these isolations. Three of the strains are putative new species with no serological relationship to any other Spiroplasma species. A fourth strain is a putative new species that may be distantly related to S. helicoides, a southeastern U.S. species. These four strains are accorded herein status as representatives of new serogroups: strain BARC 4886 (group XXXV); strain BARC 4900 (group XXXVI); strain BARC 4908 (group XXXVII); and GSU5450 (group XXXVIII). A fifth Spiroplasma species was very closely related to S. lineolae, known previously only from the Georgia (U.S.) coast. The sixth was most closely related to subgroup VIII-3, known from Texas and the southeastern U.S. Discovery of six spiroplasma species in only 13 attempted isolations reflects diversity seldom equaled in southeast Georgia, and never elsewhere in the U.S. These results are consistent with a hypothesis that spiroplasma diversity increases from north (Nova Scotia) to south (Georgia and Costa Rica). The discovery of significant affinity between some spiroplasmas of the southeastern U.S. and the Costa Rican highlands was unexpected, but may reflect a climatically complex Pleistocene history.

Factors Affecting Engorgement Behavior in the Salt Marsh Horse Fly, <Emphasis Type="Italic">Tabanus nigrovittatus</Emphasis> Macquart (Diptera: Tabanidae)

Female Tabanus nigrovittatus were field collected and used in laboratory experimentation to explore physiological and behavioral factors that affect engorgement. Previous studies showed sulfakinins act as feeding satiety factors in insects. This study demonstrates that sulfakinins have differing effects on engorgement that is dependent on the feeding technique used in the laboratory. The satiety effect of sulfakinin on flies engorging using the blood-soaked Kimwipe® feeding technique is not in agreement with previous experiments using an alternate feeding technique with artificial membranes. This study is the first to demonstrate that the temperature of blood is a significant factor for engorgement in this species. Also, the percentage of flies engorging is significantly different depending on the feeding technique used.     

Wing morphometrics as a possible tool for the diagnosis of the Ceratitis fasciventris,C. anonae,C. rosa complex (Diptera,Tephritidae)

Previous attempts to resolve the Ceratitis FAR complex (Ceratitis fasciventris, Ceratitis anonae, Ceratitis rosa, Diptera, Tephritidae) showed contrasting results and revealed the occurrence of five microsatellite genotypic clusters (A, F1, F2, R1, R2). In this paper we explore the potential of wing morphometrics for the diagnosis of FAR morphospecies and genotypic clusters. We considered a set of 227 specimens previously morphologically identified and genotyped at 16 microsatellite loci. Seventeen wing landmarks and 6 wing band areas were used for morphometric analyses. Permutational multivariate analysis of variance detected significant differences both across morphospecies and genotypic clusters (for both males and females). Unconstrained and constrained ordinations did not properly resolve groups corresponding to morphospecies or genotypic clusters. However, posterior group membership probabilities (PGMPs) of the Discriminant Analysis of Principal Components (DAPC) allowed the consistent identification of a relevant proportion of specimens (but with performances differing across morphospecies and genotypic clusters). This study suggests that wing morphometrics and PGMPs might represent a possible tool for the diagnosis of species within the FAR complex. Here, we propose a tentative diagnostic method and provide a first reference library of morphometric measures that might be used for the identification of additional and unidentified FAR specimens.