Sensation of the tiniest kind: the antennal sensilla of the smallest free-living insect Scydosella musawasensis (Coleoptera: Ptiliidae)

Miniaturization is a major evolutionary trend prominent in insects, which has resulted in the existence of insects comparable in size to some unicellular protists. The adaptation of the complex antennal multisensory systems to extreme miniaturization is a fascinating problem, which remains almost unexplored. We studied the antennal sensilla of Scydosella musawasensis Hall, 1999 (Coleoptera: Ptiliidae), the smallest free-living insect, using scanning electron microscopy. The antenna of S. musawasensis bears 131 sensilla; no intraspecific variation in the number or position of the sensilla has been revealed. Nine different morphological types of sensilla are described according to their external morphological features and distribution: four types of sensilla trichodea, one type of sensilla chaetica, two types of sensilla styloconica, and two types of sensilla basiconica. Morphometric analysis of the sensilla of S. musawasensis, based on measurements of the lengths and diameters of sensilla and their location and number, showed the absence of significant differences between females and males. Comparative allometric analysis of S. musawasensis and larger Coleoptera showed that the number of sensilla and the size of sensilla chaetica decrease with decreasing body size. However, the number of the types of sensilla and the length and diameter of the multiporous sensilla basiconica revealed no correlation with the body size. Comparison of the acquired data with the results of our earlier study of the antennal sensilla of some of the smallest parasitic wasps is used to put forward hypotheses on the common principles of miniaturization of the antennal sensory systems of insects.

Download Full-text

Antennal Sensilla of Chrysis shanghalensis (Hymenoptera: Chrysididae), a Larval Ectoparasite of Monema flavescens (Lepidoptera: Limacodidae)

Journal of Entomological Science ◽

10.18474/0749-8004-56.1.1 ◽

2021 ◽

Vol 56 (1) ◽

pp. 1-11

Author(s):

Shu Z. Yang ◽

Mei H. Yang ◽

Yun Xu ◽

Jin T. Zhang

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Natural Enemy ◽

Tree Species ◽

External Morphology ◽

Antennal Sensilla ◽

Sensilla Basiconica ◽

Sensilla Trichodea ◽

Males And Females ◽

Scanning Electron

Abstract Chrysis shanghalensis Smith (Hymenoptera: Chrysididae) is an ectoparasitoid and important natural enemy of Monema flavescens Walker (Lepidoptera: Limacodidae), a serious defoliator of a number of tree species. The external morphology of the antennal sensilla of this parasitoid was examined by scanning electron microscopy, and types and distribution of sensilla were recorded. The antennae of C. shanghalensis were geniculate in shape and composed of a scape with radicula, a pedicel, and a flagellum divided into 11 flagellomeres in males and females. Cuticular pore and 14 types of sensilla were identified on the antennae of both sexes. These included aporous Böhm's bristles, sensilla trichodea 1, 2, and 3 (nonporous), sensilla trichodea 4 (multiporous), two types of sensilla chaetica (nonporous), four morphological types of sensilla basiconica (multiporous), two morphological types of sensilla coeloconica (multiporous), and one type of sensillum campaniforme (nonporous).

Download Full-text

Between extreme simplification and ideal optimization: antennal sensilla morphology of miniaturized Megaphragma wasps (Hymenoptera: Trichogrammatidae)

PeerJ ◽

10.7717/peerj.6005 ◽

2018 ◽

Vol 6 ◽

pp. e6005 ◽

Cited By ~ 3

Author(s):

Anna V. Diakova ◽

Anastasia A. Makarova ◽

Alexey A. Polilov

Keyword(s):

Body Size ◽

The Body ◽

Parasitoid Wasps ◽

Antennal Sensilla ◽

Sensilla Styloconica ◽

Sensory Reception ◽

Unicellular Organisms ◽

Males And Females ◽

High Level ◽

Insect Antenna

One of the major trends in the evolution of parasitoid wasps is miniaturization, which has produced the smallest known insects. Megaphragma spp. (Hymenoptera: Trichogrammatidae) are smaller than some unicellular organisms, with an adult body length of the smallest only 170 µm. Their parasitoid lifestyle depends on retention of a high level of sensory reception comparable to that in parasitoid wasps that may have antennae hundreds of times larger. Antennal sensilla of males and females of Megaphragma amalphitanum and M. caribea and females of the parthenogenetic M. mymaripenne are described, including sensillum size, external morphology, and distribution. Eight different morphological types of sensilla were discovered, two of them appearing exclusively on female antennae. Two of the types, sensilla styloconica and aporous placoid sensilla, have not been described previously. Regression analyses were performed to detect and evaluate possible miniaturization trends by comparing available data for species of larger parasitoid wasps. The number of antennal sensilla was found to decrease with the body size; M. amalphitanum males have only 39 sensilla per antenna. The number of antennal sensilla types and sizes of the sensilla, however, show little to no correlation with the body size. Our findings on the effects of miniaturization on the antennal sensilla of Megaphragma provide material for discussion on the limits to the reduction of insect antenna.

Download Full-text

Fine structure and distribution of antennal sensilla of stink bug Arma chinensis (Heteroptera: Pentatomidae)

Entomologica Fennica ◽

10.33338/ef.84629 ◽

2019 ◽

Vol 25 (4) ◽

pp. 186-198 ◽

Cited By ~ 4

Author(s):

Jian Zhang ◽

Xiaojun Zhang ◽

Chunyu Liu ◽

Lipeng Meng ◽

Yulin Zhou

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Distal Part ◽

Antennal Sensilla ◽

Stink Bug ◽

Sensilla Basiconica ◽

Sensilla Trichodea ◽

Morphology And Structure ◽

Heteroptera Pentatomidae ◽

Scanning Electron

Scanning electron microscopy was used to examine the morphology, ultrastructure, and distribution of antennal sensilla of the stink bug Arma chinensis. Two types of sensilla trichodea (ST1–2), four types of sensilla basiconica (SB 1– 4), one type of sensilla chaetica (SCH), one type of sensilla cavity (SCA) and one type of sensilla coeloconica (SCO) were distinguished on the antennae in both sexes. ST1 and ST2 were absent from the scape and pedicel. SB1 were absent from the scape. SB2 were distributed throughout the antennae. SB3 were located on the second pedicel and the two flagellomeres. SB4 were absent from the second flagellomere. SCH was observed on the second pedicel and the two flagellomeres. SCA and SCO occurred only on the second flagellomere. SB1 clusters occurred on the distal part of the second flagellomere. We compared the morphology and structure of these sensilla to other Heteroptera and discuss their possible functions.

Download Full-text

Call rate in Common Cuckoos does not predict body size and responses to conspecific playbacks

Journal of Ornithology ◽

10.1007/s10336-021-01909-6 ◽

2021 ◽

Author(s):

Zoltán Elek ◽

Miklós Bán ◽

Attila Fülöp ◽

Attila Marton ◽

Márk E. Hauber ◽

...

Keyword(s):

Body Size ◽

The Body ◽

Phenotypic Traits ◽

Call Rate ◽

Cuculus Canorus ◽

Common Cuckoo ◽

Natural Rate ◽

Free Living ◽

Territorial Conflicts ◽

Call Characteristic

AbstractThe brood parasitic Common Cuckoo Cuculus canorus is best known for its two-note “cu-coo” call which is almost continuously uttered by male during the breeding season and can be heard across long distances in the field. Although the informative value of the cuckoo call was intensively investigated recently, it is still not clear whether call characteristic(s) indicate any of the phenotypic traits of the respective vocalising individuals. To fill this gap, we studied whether the call rate of male cuckoos (i.e., the number of calls uttered per unit of time) provides information on their body size, which might be a relevant trait during intrasexual territorial conflicts. We captured free-living male cuckoos and measured their body size parameters (mass, wing, tail and tarsus lengths). Each subject was then radio-tagged, released, and its individual “cu-coo” calls were recorded soon after that in the field. The results showed that none of the body size parameters covaried statistically with the call rates of individual male Common Cuckoos. In addition, we experimentally tested whether the “cu-coo” call rates affect behavioural responses of cuckoos using playbacks of either a quicker or a slower paced call than the calls with natural rates. Cuckoos responded similarly to both types of experimental playback treatments by approaching the speaker with statistically similar levels of responses as when presented with calls at the natural rate. We conclude that male Common Cuckoos do not advertise reliable information acoustically regarding their body size, and so, cuckoo calls are neither useful to characterize cuckoos’ phenotypic traits directly nor to indicate environmental quality indirectly.

Download Full-text

Observations on the Ultrastructure of Antennal Sensilla of Adult Glenea cantor (Cerambycidae: Lamiinae)

Journal of Insect Science ◽

10.1093/jisesa/ieaa013 ◽

2020 ◽

Vol 20 (2) ◽

Author(s):

Zishu Dong ◽

Yubin Yang ◽

Fugen Dou ◽

Yujing Zhang ◽

Huixin Huang ◽

...

Keyword(s):

Sexual Communication ◽

Antennal Segment ◽

Diameter Distribution ◽

Antennal Sensilla ◽

Sensilla Basiconica ◽

Future Studies ◽

Sensilla Trichodea ◽

Sensor Density ◽

Mechanical Sensing ◽

Gustatory Sensilla

Abstract The external morphology and distribution of antennal sensilla of Glenea cantor Fabricius were studied with scanning electron microscopy. The antennae of G. cantor were observed to be filiform, consisting of scape, pedicel, and flagellum (nine flagellomeres). Four distinct types of sensory receptors were observed, including sensilla chaetica, sensilla trichodea, sensilla basiconica, and Böhm bristles. Three morphological subtypes of sensilla chaetica were found on the antennae, and sensilla trichodea were also categorized into three morphological subtypes. Sensilla basiconica was grouped into two morphological subtypes that were found on subsegments F2-F9 of the flagellum, and Böhm bristles were only found at the intersegmental joints between the scape and the head and between the scape and the pedicel. The antennae of male and female adults were similar in shape, length, and diameter. However, the length, diameter, distribution, and number of each of the four distinct types of sensilla on the males were significantly different from those on females. The types, lengths, diameters, numbers, and distributions of these sensilla were described, and their possible functions were also discussed. The results indicated that the base and end of an antennal segment have a similar sensillum density, but the middle section sensor density is significantly greater, especially for olfactory and gustatory sensilla, possibly because the joints are more involved in mechanical sensing. The density of sensors is closely related to its sensing function; so, future studies on the biology of olfaction and sexual communication in G. cantor will be facilitated by these observations.

Download Full-text

Antennal Morphology and Sexual Dimorphism of Antennal Sensilla in Callitettix versicolor (Fabricius) (Hemiptera: Cercopidae)

Insects ◽

10.3390/insects10020056 ◽

2019 ◽

Vol 10 (2) ◽

pp. 56 ◽

Cited By ~ 3

Author(s):

Qing Zhu ◽

Nan Wu ◽

Jolanta Brożek ◽

Wu Dai

Keyword(s):

Sexual Dimorphism ◽

Background Information ◽

Economic Damage ◽

Antennal Sensilla ◽

Male And Female ◽

Sensilla Basiconica ◽

Sensilla Trichodea ◽

Important Pest ◽

First Time ◽

Fine Morphology

The rice spittlebug Callitettix versicolor (Fabricius) is an important pest of rice and maize in South Asia and causes severe economic damage. To provide background information for chemical ecology studies, the fine morphology of antennae and the types and distribution of the sensilla on the male and female antennae of Callitettix versicolor (Fabricius) are investigated by means of scanning electron microscopy (SEM). Results show that the antenna is filiform and composed of three segments: a scape, a pedicel, and a flagellum. The female antennae are slightly shorter than the male antennae. In both sexes, four types and nine subtypes of sensilla were observed: sensilla basiconica (SB1, SB2), sensilla campaniformia (SCa1, SCa2 and SCa3), sensilla coeloconica (SCo1, SCo2 and SCo3) and sensilla trichodea (ST). In addition, sensilla coeloconica (SCo1) are observed on the membrane of the top of the pedicel in Cercopidae for the first time. Sexual dimorphism mainly occurs in variation in the number of sensilla coeloconica (SCo2, SCo3) on the bulb-shaped portion of the flagellum and in the shape of sensilla basiconica (SB2). There are significantly more sensilla coeloconica in males than in females. The external structure and distribution of these sensilla are compared to those of other cercopids and possible functions of the antennal sensilla are discussed.

Download Full-text

Scanning electron microscopy of the antennal sensilla in female Culicoides paraensis (Diptera: Ceratopogonidae)

Memórias do Instituto Oswaldo Cruz ◽

10.1590/s0074-02761989000400002 ◽

1989 ◽

Vol 84 (4) ◽

pp. 463-469 ◽

Cited By ~ 4

Author(s):

M. L. Felippe-Bauer ◽

P. G. Bauer ◽

F. C. Silva Filho

Keyword(s):

Electron Microscopy ◽

Host Preference ◽

Type I ◽

Antennal Sensilla ◽

Sense Organs ◽

Biting Midges ◽

Sensilla Basiconica ◽

Sensilla Trichodea ◽

Scanning Electron

We studied by sanning electron microscopy the number, types, structure and distribution of the antennal sensilla of the medical important ceratopogonid Culicoides paraensis (Goeldi). There are about 174 sense organs on the antenmal flagellum which are classified as sensilla chaetica; sharp-tipped and blunt-tipped (type I and II) sensilla trichodea; sensilla basiconica; sensilla coeloconica; sensilla ampullacea and styloconic-type sensilla. The role of antennal sensory organs are discussed regarding the host preference of the biting midges.

Download Full-text

Morphology and Distribution of the Antennal Sensilla of Two Species, Megalurothrips usitatus and Thrips palmi (Thysanoptera: Thripidae)

Insects ◽

10.3390/insects10080251 ◽

2019 ◽

Vol 10 (8) ◽

pp. 251 ◽

Cited By ~ 1

Author(s):

Xiao-Shuang Wang ◽

Ali Shaukat ◽

Yun Han ◽

Bo Yang ◽

Liang-De Tang ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Chemical Communication ◽

Antennal Sensilla ◽

Sensilla Basiconica ◽

Sensilla Trichodea ◽

Sensilla Styloconica ◽

Thrips Palmi ◽

Scanning Electron

The morphology and distribution of the antennal sensilla of Megalurothrips usitatus Bagnall and Thrips palmi Karny were examined using scanning electron microscopy (SEM). These are serious pests of various economically important crops, and their antennae are important in chemical communication. The antennae of both species consist of a scape, pedicel, and flagellum, but the flagellum of M. usitatus is made up of six sub-segments, whereas that of T. palmi consists of five sub-segments. Seven morphological sensilla types, including Böhm bristle (BB), sensilla campaniformia (Sca), three types of sensilla basiconica (Sb1, Sb2 and Sb3), two types of sensilla chaetica (Sch1 and Sch2), sensilla styloconica (Sst), sensilla trichodea (St), and sensilla cavity (Scav), were recorded in both species. The scape and pedicels exhibited Sch1, BB and Sca. The flagellum exhibited two types of Sch, three types of Sb, St, Sst and Scav. Based on these results, the putative function of the sensilla of M. usitatus and T. palmi are also discussed.

Download Full-text

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

Canadian Journal of Zoology ◽

10.1139/z85-054 ◽

1985 ◽

Vol 63 (2) ◽

pp. 355-362 ◽

Cited By ~ 23

Author(s):

Michel J. Faucheux

Keyword(s):

Antennal Sensilla ◽

Sensilla Basiconica ◽

Sensilla Trichodea ◽

Tineola Bisselliella

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.

Download Full-text

Morphological and Ultrastructural Characterization of Antennal Sensilla and the Detection of Floral Scent Volatiles in Eupeodes corollae (Diptera: Syrphidae)

Frontiers in Neuroanatomy ◽

10.3389/fnana.2021.791900 ◽

2021 ◽

Vol 15 ◽

Author(s):

Wan-Ying Dong ◽

Bing Wang ◽

Gui-Rong Wang

Keyword(s):

Electron Microscopy ◽

Floral Scent ◽

Sensory Cells ◽

Ultrastructural Organization ◽

Antennal Sensilla ◽

Olfactory Sensilla ◽

Sensilla Basiconica ◽

Sensilla Trichodea ◽

Transmission Electron ◽

Olfactory Organs

The olfactory sensing system of the syrphid fly Eupeodes corollae is essential in pollination and prey localization, but little is known about the ultrastructural organization of their olfactory organs. In this study, the morphology, distribution, and ultrastructural organization of antennal sensilla of E. corollae in both sexes were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Neuronal responses of a subtype of sensilla basiconica to floral scent compounds were recorded by single sensillum recording (SSR). Ten morphological types, including Böhm bristles, sensilla chaetica, microtrichiae, sensilla trichodea, sensilla basiconica, sensilla clavate, sensilla coeloconica, sensilla styloconica, sensilla placodea, and sensory pit, were identified. Except for Böhm bristles and sensilla chaetica, which were distributed on the scape and pedicel of E. corollae antennae, innervated sensilla were densely distributed on the flagellum, a vital sensory organ. Further, observing ultrastructural organization showed that the sensilla trichodea, basiconica, and clavate are single-walled with multiple nanoscale pores perforating the cuticle. Sensilla coeloconica are double-walled and have no wall pores, but instead, have longitudinal grooves along with the pegs. Sensilla chaetica, Böhm bristles, and microtrichiae did not have wall pores on the cuticle or sensory cells at the base. The SSR results indicated that neuron B housed in the subtype of sensilla basiconica I (SBI) mainly responded to methyl eugenol and other aromatic compounds. Overall, our results provide valuable information to understand the morphology and ultrastructure of antennal sensilla from E. corollae. These findings are beneficial for the studies of the neuronal function map of olfactory sensilla and for determining evolutionary relationships in Diptera.

Download Full-text