Basiconic Capitate Peg Sensilla Research Articles

Morphological analysis of sensilla on different organs in Pachyneuron aphidis, a hyperparasitoid of Myzus persicae.

Aphidius gifuensis is the main enemy of Myzus persieae. While its parasitic rate can be influenced by the hyperparasitoid, Pachyneuron aphidis. As important parts of insects to sense odors from various environments, study of sensilla can lay the foundation of the further study about the parasitic mechanisms, reduce the hyperparasitic rate, and make the most effect usage of A. gifuensis. Here, we give a fundamental study about the morphology of the sensilla on the whole body of male and female P. aphidis. We observed seven main types of sensilla on them totally by using scanning electron microscopy. Including Böhm bristle (BB), chaetica sensilla (ChS), basiconic sensilla (BS), trichoid sensilla (TS), and placodea sensilla (PS), coeleoconica sensilla (CoS), basiconic capitate peg sensilla (BCPS). In addition, TS on antennae can be divided into four subtypes, on wings can be divided into two subtypes. Sensilla were most abundant on the antennae. We observed all types of sensilla on antennae. TS4 was uniporous and PS was multiporous. The other sensilla were nonporous. We did not find sexual dimorphism with regards to sensilla on the antennae except for the location of CoS. In male, CoS situated on the fourth subsegment of flagellum, but on the eighth subsegment in female. In other organs, TS has the largest number. We also found BS on compound eyes and ovipositor, BB on thoracic legs. The possible roles of these sensilla played in life activities are discussed. Our study makes a contribution of the parasitic mechanism of hyperparasitoids.

Comparison of the antennal sensilla of females of four fig-wasps associated with Ficus auriculata

A comparison was performed of the antennal sensilla of females of four chalcid wasp species Ceratosolen emarginatus Mayr, 1906, Sycophaga sp., Philotrypesis longicaudata Mayr, 1906, and Sycoscapter roxburghi Joseph, 1957, which are specific and obligatory associated with Ficus auriculata (Lour, 1790). The four species exhibit different oviposition strategies in the fig ovules where their offspring hatch and develop. Antennal sensilla morphology was evaluated using scanning electron microscopy. Females of the four species present 11 morphologically similar types of sensilla: trichoid sensilla, sensilla obscura, chaetica sensilla 1 and 2, which all have mechanosensory functions; uniporous basiconic sensilla, which are presumably contact chemosensilla; basiconic capitate peg sensilla, coeloconic sensilla 1, multiporous basiconic and placoid sensilla, which may be regarded as olfactory sensilla, and coeloconic sensilla 2 and 3, which are presumed to be proprioreceptors or pressure receptors. The four species have significant differences in the abundance and arrangement of trichoid sensilla and chaetica sensilla 1 on the flagellum. The coeloconic sensilla and sensilla obscura only occur on the antennae of C. emarginatus that enter figs. The chemosensilla which are presumably involved in host discrimination, i.e., basiconic sensilla, multiporous placoid sensilla and basiconic capitate peg sensilla, are similar in shape and configuration, although they present some differences in abundance. These findings provide practical information on the adaptations of fig wasps and the relationship between multisensory antennae and functions in fig wasp behaviour.

Antennal sensilla morphology of Theocolax elegans (Westwood) (Hymenoptera: Pteromalidae), a larval parasitoid of the maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae)

The antennal sensilla of Theocolax elegans (Westwood) (Hymenoptera: Pteromalidae), a larval parasitoid of the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) were investigated using scanning electron microscopy. The antennal sensilla of female and male wasps appeared similar in shape and types. Antennal sensilla in female and male T. elegans were classified into four groups: basiconic capitate peg sensilla, chaetica sensilla (types 1–5), placoid sensilla and trichoid sensilla. Chaetica sensilla type 5 were found only on the female antenna. These four groups of antennal sensilla probably function as proprioceptors, hygro- and thermo- mechanoreceptors or contact chemoreceptors. The receptors are involved in host examination, host discrimination, host recognition and host location by female and male T. elegans.

Aggressive Behavior and the Role of Antennal Sensillae in the Termite Reticulitermes chinensis (Isoptera: Rhinotermitidae)

This study examined aggressive behavior between the colonies in the termite Reticulitermes chinensis from China. Strong aggression was observed among workers and soldiers. Intercolonial aggression was strong during the first 0.5 h and then reduced gradually in all the treatments. After cutting the five terminal antennal segments of workers and soldiers, there was still strong intercolonial aggression among workers and soldiers. However, after removal of the ten terminal antennal segments of workers and soldiers, almost no intercolonial aggression happened among workers and soldiers. SEM results of antennae indicated that antennal sensillae mainly occurred on the ten terminal segments including four types of trichode sensilla, both in workers and soldiers of this species. Few antennal sensilla occurred on the basal segments except for a few sensilla chaetica and basiconic capitate peg sensilla. The above findings suggest that antennal sensillae may play a role in nestmate recognition in R. chinensis.

Ultrastructure of antennal sensilla of an autoparasitoid Encarsia sophia (Hymenoptera: Aphelinidae)

Encarsia sophia (Hymenoptera: Aphelinidae) is a parasitoid utilized for biological control of Bemisia tabaci, with selection of prey aided by chemoreceptor organs. The morphology and distribution of the antennal sensilla (chemoreceptors) of E. sophia were examined using Transmission electron micrographs. The total antennal length for E. sophia was 429.28±0.95μm for females and 437.19±8.21 for males, and each antennae was found to consist of seven sensilla of different types. Both sexes possessed sensilla chaetica, sensilla trichodea, basiconic capitate peg sensilla, multiporous grooved-surface placoid sensilla (MG-PS), uniporous rod-like sensilla, nonporous finger-like sensilla, and sensilla coeloconica. Transmission electron micrographs of longitudinal sections of female antennae showed that they were composed of fat body, cuticle, mesoscutello-metanotal muscles, neurons, and glandular tissue, and cross-sections of the basal MG-PS showed sensillar lymph cavities and dendrites. The MG-PSs were imbedded in an electron-dense mass with cuticular invaginations which acted as pores that connected to a central lumen. The possible function of each type of sensilla is discussed.

Types, Morphologies and Distributions of Antennal Sensilla ofQuadrastichus erythrinae(Hymenptera: Eulophidae)

To uncover the relationship between chemical receptors and behaviors of the erythrina gall wasp (EGW), Quadrastichus erythrinae Kim (Hymenptera: Eulophidae), and to elucidate the chemical connections between the parasite and the host plant, the present study focused on determining the types, morphologies and distributions of the various antennal sensilla of adult EGW. With scanning electron microscopy and 3-dimensional microscopy, we found that the antennae of EGW adults have 6 kinds of sensilla, namely, sensory pore sensilla, chaetica sensilla, multiporous plate sensilla, trichoid sensilla, basiconic capitate peg sensilla and uniporous trichoid sensilla. Both the male and female wasps have these 6 kinds of sensilla. However the types and numbers of sensilla on the funicle and clava differed between males and females, but such a difference was not seen on the scape and pedicel between the 2 sexual genders. We found one kind of sensillum located on the end of pedicel of Q. erythrinae Kim that has not been described previously. The results of our research may aid use of EGW in the biological control of undesirable Erythrina spp. trees.

Antennal sensilla of female Encarsia guadeloupae Viggiani (Hymenoptera: Aphelinidae), a nymphal parasitoid of the spiraling whitefly Aleurodicus dispersus (Hemiptera: Aleyrodidae)

Encarsia guadeloupae Viggiani (Hymenoptera: Aphelinidae) is a minute, obligate endoparasitoid against the spiraling whitefly Aleurodicus dispersus nymph. The external morphology and distribution of the antennal sensilla of female E. guadeloupae were observed by scanning electron microscopy. Antennae of female E. guadeloupae were geniculate in shape, which consist of scape with a radicula, pedicel, and flagellum. Eight morphological sensilla types were recorded in the females: nonporous sensilla chaetica (CH-NP) and nonporous sensilla trichodea (ST-NP); uniporous sensilla chaetica (CH-UP) and uniporous sensilla trichodea (ST-UP) with a tip pore, basiconic capitate peg sensilla with numerous pores open at the bottom of the grooves; multiporous sensilla placoid (MSP) with the multiporous cuticular structure; uniporous rod-like sensilla (RO-UP) with robust grooved surfaces and the tremendous apical hole; nonporous finger-like sensilla (FI-NP) with abundant pimples at the bulgy, mortar-shaped short stalk. In order to further explore the host location mechanisms and courtship behavior of E. guadeloupae, the possible roles of the antennal sensilla of this species were discussed.

External morphology of Trichogramma dendrolimi matsumura (hymenoptera: Trichogrammatidae) organ and ultrastructure of the sensilla

In this article, we described the ultrastructure of the sensilla on the antenna, eyes, mouthparts, wings, legs, and external genitalia of female and male Trichogramma dendrolimi using scanning electron microscopy (SEM). The antenna possessed the most sensilla types. We found 13 types of sensilla on female antenna, which were trichoid sensilla (TS) type 1-4, chaetica sensilla (ChS) type 1-2, campaniform sensilla (CaS), falcate sensilla, placoid sensilla (PS) type 1-2, basiconic capitate peg sensilla (BCPS) type 1, coeloconic sensilla (CoS), and styloconic sensilla. Ten types of sensilla were found on the male antenna, some were the same as that on female T. dendrolimi antenna, such as TS types 1 and 3, CaS, PS type 1, BCPS type 1, and CoS, but TS types 5 and 6, ChS type 3, and BCPS 2 were specific to male T. dendrolimi antenna. The leg possesses eight types of sensilla and a kind of tympana structure. Four types of TSs were found on the wings. On the mouthparts, sensilla on the maxillary and labial palps were unique, including two TSs and one ChS. The ovipositor possesses three types of sensilla, and the copulatory organ possesses two types. The eyes had only one kind of TS. Furthermore, external morphology of antenna and external genitalia revealed distinct sexual dimorphisms. According to their morphology, the possible functions of these sensilla were discussed. These results may further our understanding of the sensory mechanisms of T. dendrolimi in response to infochemicals within the environment.

Ultrastructure of antennal sensilla of female Ceratosolen solmsi marchali (Hymenoptera: Chalcidoidea: Agaonidae: Agaoninae)

AbstractFig-pollinating wasps are phytophagous wasps that mainly use olfaction to locate their fig (Ficus L., Moraceae) hosts. To provide a morphological framework for studying agaonid olfaction, we examined the antennal sensilla of female Ceratosolen solmsi marchali Mayr by scanning and transmission electron microscopy. We identified and characterized (ultrastructure, distribution, abundance, and position) 13 types of sensilla: multiporous placoid sensilla (types 1 and 2), basiconic sensilla (types 1 and 2), basiconic capitate peg sensilla, sensilla chaetica (types 1–3), sensilla trichodea, sensilla coeloconica (types 1–3), and one specialized sensillum regarded as a sensillum obscurum. We suggest that five types are chemoreceptors because they are porous and innervated by multiple sensory neurons. Sensilla coeloconica type 1 may also function as chemoreceptors, based on external morphology. Other sensilla may be involved in mechanoreception, thermo- and (or) hygro-reception, or pressure detection. We discuss our results in relation to the lifestyle of C. solmsi marchali.

Antennal sensory receptors of Pteromalus puparum female (Hymenoptera: Pteromalidae), a gregarious pupal endoparasitoid of Pieris rapae

The external morphology of the antennal sensilla of Pteromalus puparum females (Hymenoptera: Pteromalidae) is described using scanning electron microscopy. The antennae of P. puparum females are geniculate in shape, formed from a large, cylindrical scape with a basal radicel fitting into the antennal socket, a shorter, barrel-shaped pedicel and a flagellum composed of 12 subsegments. Eight morphologically distinct types of sensilla were found on the female antennae. These are: nonporous sensilla trichodea types 1 and 2, which are putative mechanosensilla, nonporous sensilla chaetica, which may function as proprioceptors, uniporous sensilla trichodea types 3 and 4, which are presumably contact chemosensilla, basiconic capitate peg sensilla, which probably function in thermo-hygro reception, multiporous sensilla trichodea, and multiporous sensilla placodea which are all presumed to be olfactory sensilla.

Scanning electron microscopy studies of antennal sensilla of Pteromalus cerealellae (Hymenoptera: Pteromalidae)

Pteromalus cerealellae (Ashmead) (Hymenoptera: Pteromalidae) is an ectoparasitoid of several insect pests of stored products. In order to provide requisite background information to support our ongoing research on its host location mechanisms, we examined the external morphology of the antennal sensilla of this parasitoid using scanning electron microscopy. Antennae of male and female P. cerealellae are geniculate in shape, ∼1300 μm in length, and consist of 15 antennomeres. Eight morphological sensilla types were recorded in both sexes, including four types of the highly abundant and widely distributed sensilla trichodea (types I, II and IV are aporous while type III is multiporous), basiconic capitate peg sensilla, coeloconic sensilla, chaetica sensilla, and the most conspicuous plate-like placoid sensilla. Detailed examination of sensilla morphological features including pore presence and numbers suggest that the multiporous type III sensilla trichodea and the multiporous placoid sensilla may play a role in olfaction, whereas the uniporous chaetica sensilla may function as contact chemoreceptors. The types I and II sensilla trichodea are presumably mechanosensory, while the type IV sensilla trichodea may function as proprioceptors. The basiconic capitate peg sensilla and coeloconic sensilla probably function in thermo-hygro reception. Although the shape, structure, and size of antennae of males and female were basically similar, major differences were recorded between the sexes in the distribution of some sensilla types. The type II sensilla trichodea and the multiporous placoid sensilla are relatively more abundant in females, whereas males have greater number of the multiporous type III sensilla trichodea than females. These results are discussed in relation to the possible roles of the sensilla types in the host location behavior of P. cerealellae.

External morphology of antennal sensilla of trichogramma australicum girault (Hymenoptera : Trichogrammatidae)

External morphology of antennal sensilla on female and male Trichogramma australicum (Hymenoptera : Trichogrammatidae) was examined using scanning electron microscopy. Antennae show strong sexual dimorphism in structure and types of sensilla. The female antenna displays 14 types of sensilla: basiconic capitate peg sensilla (types 1 and 2), campaniform sensilla, chaetica sensilla (types 1–3), coeloconic sensilla, falcate sensilla, placoid sensilla (types 1 and 2), styloconic sensilla and trichoid sensilla (types 1–3). The male antenna displays 12 types of sensilla: basiconic capitate peg sensilla (type 2), campaniform sensilla, chaetica sensilla (types 1–5), coeloconic sensilla, placoid sensilla (type 1), and trichoid sensilla (types 3–5). Falcate and styloconic sensilla occur only on the female antenna. Both sensilla probably are associated with host examination, host discrimination and oviposition behaviour. Male antennal trichoid sensilla types 4 and 5 are probably associated with courtship behaviour, because these types occur only on the male. We propose the term “falcate sensilla” for a unique female antennal sensilla; the number of falcate sensilla may be used for identification of Trichogramma spp. In addition, we report the presence of placoid sensilla type 2 and difference in structure of coeloconic sensilla in T. australicum. Variation in structure and position of antennal sensilla are discussed.

Trichogramma pretiosum and a New Cryptic Species Occurring Sympatrically in Southwestern North America (Hymenoptera: Trichogrammatidae)

Trichogramma pretiosum Riley, the most widespread and important member of its genus in North America, occurs with a similar and previously undetected species over a large part of its range. This new species, T. deion Pinto & Oatman, can be separated by the number of basiconic capitate peg sensilla on the antennae and by minor differences in male genitalia. Seasonal, geographic, host, and habitat distributions of the two species are compared.