Scanning electron morphological studies of Tribolium confusum Jacquelin du Val (Coleopteran: Tenebrionidae)
© The Author(s) 2017
Received: 30 May 2017
Accepted: 21 August 2017
Published: 26 September 2017
The confused flour beetle Tribolium confusum Jacquelin du Val (Coleopteran: Tenebrionidae) is the most destructive pest of stored products worldwide. It is the most common pest of wheat flour.
This study describes and illustrates the larvae, pupae, and adults of T. confusum using scanning electron microscopy. The first larval instars are 5.0–5.1 mm long and 0.5–0.6 mm wide whereas the last larval instars are 5.75–6.9 mm long and 0.75–0.95 mm wide. Adults of T. confusum are reddish brown elongate beetles (4.0–4.5 mm in body length and 1.0–1.2 mm in width). Electron micrographs revealed the structure of the mouth parts during the larval, pupal, and adult stages as well as the structure of thoracic and abdominal appendages. Results indicated that the setiferous sex patches which were reported in males can often be used for sexing specimens. A specific feature of the first instar larvae of T. confusum is the extreme shortened antenna with a reduced number of antennomeres and the presence of well-developed and moderately long legs.
SEM examination may help us not only discover and understand new morphological details as the pits with spine on the elytra and the spikes on the membrane wings which will facilitate the identification of this species but also clarify the functions of various body parts.
Tenebrionidae is one of the most diverse families within Coleoptera (beetles) and is very difficult to classify (Aalbu, Triplehorn, Campbell, Brown, Somerby, et al., 2002).
Studies of immature and adult stages of insects are very important and useful for classification of particular groups which were seeing several times (Beutel & Friedrich, 2005).
Taxonomic studies on immature stages of the family Tenebrionidae are rare because the knowledge about the developmental stages of this family is very limited (Jia, Ren, & Yu, 2013). This is particularly true for tenebrionid pupae and larvae. For the tenebrionid pupae, several workers have made their contributions as (Daggy, 1946; Abdulla, 1964; Spilman, 1966, 1969; Bouchard & Steiner, 2004; Cherney, 2006; Gosik, 2007; Dunford & Steiner, 2007; Simoes et al., 2009; Matthews et al., 2010 and Jia et al., 2013), but few studies including the tribe Optrini, was reported by Cherney (2005) and Cherney and Fedorenko (2006).
The red flour beetle, Tribolium confusum (Coleoptera: Tenebrionidae), is the most widespread and withering major insect pest of stored cereals in the world. Hana (2013) had reported the percentage of damages of these insects ranging from 5 to 30% of the world’s total agriculture production. Freeman (1973) had reported that the success of the spreading of these insects is due to different evolutionary adaptations to the actions of humans who transport them through the world and give a protective habitat for stored food stuffs.
The aim of the present work was to study the morphology of different stages of T. confusum to explore new morphological details which will facilitate the identification of different stages of this species.
All experiments were done according to the guidance and animal care ethics of Sohag University, Egypt. Larvae, pupae, and adults of T. confusum were collected from the flour in the laboratory and fixed in 70% alcohol. Pupae were examined using binocular microscope to differentiate between male and female pupae. Specimens were prepared for examination by subjecting them to dehydration series of 90%, 95%, and absolute alcohol. Specimens were then critically point dried and coated with gold using sputter coating for examination using a scanning electron microscope (SEM), JEOL, JSM 5300.
General body shape of the larvae is as follows: elongate, cylindrical, body mostly white, weakly sclerotized surface with sparse vestiture of whitish setae, segment IX dorsally forming divided sclerite (pygidium) (Fig. 7a–d). Urogomphi are appendages of tergum IX of beetle larvae of T. confusum which are reported for the first and last larval instars (Fig. 7c, d). Segment X is not visible in dorsal view; it is inserted on the ventral side posterior to sternum IX and may be represented by two lobes (Fig. 7c, d) and (Fig. 9b) which is probably developed as a pygopod. In the larval stage, there were three pairs of legs each of them consists of five segments (Figs. 7a and 9a); these are coax, trochanter, femur, tibia, and tarsus, and a single claw is present in the first and last instar larvae.
Experiments carried out by Huet and lenoir-Rousseaux (1976) and Daly and Sokoloff (1965) on the tenebrionid beetle Tenebrio molitor demonstrated that the entire larval appendage developed to the adult appendage and that specific adult structures within each appendage generally arise by transformation of their corresponding larval structure. Thus on the basis of its relatively close relationship with Tenebrio (Daly & Sokoloff, 1965) on T. castaneum (David, Frank, Ariel, Moto, & Elizabeth, 2012), the adult mouth parts are assumed to be formed by transformation of their larval precursors. This contrasts with Drosophila, where larval appendages exist as small sensory organs and adult appendages develop from imaginal discs that are set aside during embryonic development (David et al., 2012).
In the present study, a specific feature of the first instar larvae of T. confusum is the extreme shortened antenna with a reduced number of antennomeres; these results agree with that reported by Ross and Pothecary (1970), Beutel and Hornschemeyer (2002), and Margarita et al. (2015). Another feature is the presence of well-developed and moderately long legs; these results agree with that reported by Ross and Pothecary (1970) and Margarita et al. (2015).
Urogomphi are appendages of tergum IX of beetle larvae of T. confusum which are reported for the first and last larval instars. Urogomphi are prominences of tergum IX of beetle larvae (e.g., Lawrence et al., 2010). In some alticine (e.g., Chaetocnema and Psylliodes) and galerucine (e.g., Diabrotica duodecimpunctata, D. vittata) larvae, a pair of simple curved urogomphi is present. A single median terminal process occurs in larvae of Phyllotreta cruciferae, P. atra, and P. vittula (Boving, 1930; Cox, 1988; Cox, 1981). Yi et al. (2014) reported that segment IX is dorsally forming undivided semicircular and subtriangular sclerite (pygidium) for galerucine and alticine larvae.
In the present study, after describing the different stages of T. confusum, the urogomphi of the pupae are diverging from each other, these results agree with that reported by Jia et al. (2013) who identified two main types of urogomphi in the Optartini pupae. The urogomphi in Scleropotrum horridum horridum, Gonocepholum reticulatum, Opatrum (Opatrum) subaratum, Penthicus (Myladion) alashanicus, Penthicus (Myladion) nojonicus, and Melanesthes (Optroneshes) rugipennis are identical. In these species, the urogomphi are diverging from each other. Also, Jia et al. (2013) reported that the urogomphi in Eumylada potonini, Eumylada punctifera, Melanesthes (Melanesthes) maxima maxima, Melanesthes (Melanesthes) jintaiensis, and Myladina unguiculina are parallel to each other.
Also, Steiner (2014) described the pupa of Glyptotus cribratus which is bearing large divergent urogomphi. The urogomphi of pupa of Cibdelis blaschkei are long, wrinkled at base, gradually tapered to divergent sharp apices.
In the present study, T. confusum on the first and last larval instar, segment X is not visible in dorsal view, it is inserted on the ventral side posterior to sternum IX and may represented by two lobes which are probably developed as a pygopod. These results agree with that reported by Margarita et al. (2015) who reported the structure of segment X for the first larval instar of Tenomerga mucida that the greatly reduced segment X is inserted on the ventral side posterior to sternum IX, it is represented by two pairs of flattened, sclerotised anal flaps, the larger flap bears two long setae, the smaller ventromesal flap one long seta, and several short ones along its rounded posterior edge; the latter are fused basally but divided by a deep median cleft.
In contrast to Steiner (2014) who reported the absence of pygopods on the mature larva of Glyptotus cribratus, the abdominal segment X is small, ventral, transverse, semi-circular, convex, three times wider than long, with row of six fine setae across width. Also, Steiner (2014) described the mature larva of Cibdelis blaschkei in which abdominal segment X is small, ventral, transverse, semi-circular, convex, 2.5× wider than long, with a row of six fine setae across width, and pygopods absent.
Beutel and Hornschemeyer (2002) reported that the eversible ventral lobes of segment IX are composed of a weakly sclerotized proximal part and a largely membranous distal element is present in larvae of Micromalthus and Cupedidae (Lawrence, 1991). Beutel and Hornschemeyer (2002) reported that the eversible ventral lobes of segment IX may facilitate locomotion in galleries. Also, Beutel and Hornschemeyer (2002) reported that segment X is not visible externally in all larvae of Archostemata. It is exposed in larvae of most other groups of Coleopteran (e.g., Adephaga, Staphyliniformia) (Frank, 1991; Newton, 1991).
Beutel and Hornschemeyer (2002) reported the absence of urogompi from tergum IX of all larvae of Archostemata but they are present in most larvae of Adephaga, in Torridincolidae (Beutel, 1999b) and in larvae of many groups of Polyphaga (e.g., Hydrophiloidea, Histeroidea, and Staphylinoidae) (Frank, 1991; Newton, 1991).
In the present study, the presence of setiferous patches on the fore, middle, and hind femur of the legs were reported in male of T. confusum. Their basic structure, comprising a depression-containing dense, fluted or grooved setae, and numerous pores, is similar to that found in the setiferous sex patches of other Coleoptera (Faustini & Halstead, 1982).
So, using SEM examination add some knowledge about morphological details of different stages of T. confusum, the setiferous sex patches in males, the structure of the mouth parts of adult and larval stage, the pits with spine on the elytra, and the spikes on the membrane wings which will facilitate the identification of T. confusum and may help to clarify the functions of various body parts.
Based on the current results, the future work will concern mainly with the morphological, histological, and biochemical studies of this species and others.
I would like to express my thanks to the SEM unit, Assuit University, for their efforts in specimen preparation. Great thanks to the Dean of Faculty of Science (Sohag University) for funding this work.
NMHZ is the main author only for this manuscript.
Consent for publication
I agree to the publication.
The author declares that he/she has no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
- Aalbu, R. L., Triplehorn, C. A., Campbell, J. M., Brown, K. W., Somerby, R. E., & Thomas, D. B. (2002). Tenebrionidae Latreille 1802. In R. H. Arnett, M. C. Thomas, P. E. Skelley, & J. H. Frank (Eds.), American beetles, (vol. 2, pp. 463–509). Boca Raton: CRC Press. https://doi.org/10.1201/9781420041231.ch7.Google Scholar
- Abdulla, M. (1964). The immature stages of a south Indian Cryphoeus (Coleoptera: Tenebrionidae). Proceeding of the Royal Entomological Society of London, 39, 153–156.View ArticleGoogle Scholar
- Beutel, R. G. (1999). Description of the larva of Satonius kurosaw Google Scholar
- Beutel, R. G., & Friedrich, F. (2005). Comparative study of larvae of Tenebrionoidea ( Cucujiformia, Coleoptera ). European Journal of Entomology, 102, 241–264.View ArticleGoogle Scholar
- Beutel, R. G., & Hornschemeyer, T. (2002). Larval morphology and phylogentic position of Micromalthus debilis LeConte (Coleoptera:Micromalthidae). Systematic Entomology, 27, 169–190.View ArticleGoogle Scholar
- Bouchard, P., & Steiner, W. (2004). First descriptions of Coelometopini pupae (Coleoptera: Tenebrionidae) from Australia, Southeast Asia and the Pacific region, with comments on phylogenetic and relationships and antipredator adaptations. Systematic Entomology, 29, 101–114.View ArticleGoogle Scholar
- Boving, A. G. (1930). Description of the larva of Cerotom trifurcate Foster (Coleoptera: Chrysomelidae). Proceedings of the Entomological Society of Washington, 32, 51–58.Google Scholar
- Cherney, L. S. (2005). Darkling-beetles (Coleoptera: Tenebrionidae). Fauna of Ukraine. Beetles, 19(10), 431 Kiev, Naukova Dumka, (In Russian).Google Scholar
- Cherney, L. S. (2006). Morphology of Preimaginal stages of some species of beetles ( Coleoptera: Tenebrionidae) darkling of the Fauna of Ukraine. Vestrik Zoology, 40(4), 351–358 (In Russian).Google Scholar
- Cherney, L. S., & Fedorenko, L. V. (2006). Keys to darkling beetles (Coleoptera:Tenebrionidae) of Fauna of Ukraine (imago, larvae, pupae), (p. 247). Kolobig: Kiev (In Russian). Coleoptera: Torridincolidae). Water Beetles of China, 2:53–59. Google Scholar
- Cox, M. L. (1981). Of notes on the biology Orsodacne Latreille with a subfamily key to the larvae of the British Chrysomelidae (Coleoptera). Entomologistۥs Gazette, 32, 123–135.Google Scholar
- Cox, M. L. (1988). Egg bursters in the Chrysomelidae, with a review of their occurrence in the Chrysomeloidae and Curculionoidae (Coleoptera). Systematic Entomology, 13, 393–432.View ArticleGoogle Scholar
- Daggy, T. (1946). Notes on the ecology and taxonomy of certain pupae of the family Tenebrionidae (Coleoptera). Proceedings of the Indiana Academy of Sciences, 56, 253–260.Google Scholar
- Daly, H. V., & Sokoloff, A. (1965). Labiopedia, a sex-linked mutant in Tribolium confusum Duval (Coleoptera:Tenebrionidae). Journal of Morphology, 117, 251–269.View ArticlePubMedGoogle Scholar
- David, R. A., Frank, W. S., Ariel, C. A., Moto, K., & Elizabeth, L. J. (2012). Patterning of the adult mandibulate mouthparts in the red beetle, Tribolium castaneum. Genetics, 190, 639–654.View ArticleGoogle Scholar
- Dunford, J.C. and Steiner, W.E. (2007): Madagascar beetle, Leichenum canaliculatum variegatum (King) (Insecta: Coleoptera: Tenebrionidae). University of Florida. IFAS extension EENY. 399(IN723): 1–7.Google Scholar
- Faustini, D. L., & Halstead, D. G. H. (1982). Setiferous structures of male Coleoptera. J. Morpgol, 173, 43–72.View ArticleGoogle Scholar
- Frank, J. H. (1991). Staphylinidae ( Staphylinoidea ) ( including Brathinidae, Empelidae ). In F. W. Stehr (Ed.), Immature insects, (vol. 2, pp. 341–352). Dubuque: Kendall/Hunt Publishing Co.Google Scholar
- Freeman, J. A. (1973). Infestation and control of pests beetle of stored grain in international trade. In R. N. Sinha, & W. D. E. Muir (Eds.), Grain storage part of a system, (pp. 99–136). Westport: Avi Publ. Co. Inc.Google Scholar
- Gosik, R. (2007). Description of the pupa of Mcetochora axillaris (Paykull,1799)(Coleoptera:Tenebrionidae). Baltic Journalof Coleopterology, 7, 179–184.Google Scholar
- Hana, H. M. (2013). Repellency of Ethanolic extract of some indigenous plants against Tribolium confusum (du val) (Coleoptera: Tenebrionidae). IOSR Journal of Agriculture and Veterinary Science, 2, 27–31.View ArticleGoogle Scholar
- Huet, C., & Lenoir-Rousseaux, J. J. (1976). Etude de la mise en place de la patte imaginable de Tenebrio molitor. Analyse experimentale des processus de restauration au cours de la morphogenese. J. Embryol. Exp. Morphol, 35, 303–321.PubMedGoogle Scholar
- Jia, L., Ren, G. D. and Yu, Y. Z. (2013): Descriptions of eleven Opatrini pupae (Coleoptera: Tenebrionidae) from China.Google Scholar
- Lawrence, J. F. (1991). Ommatidae (Archostemata) (=Ommatidae, including Tetraphaleridae), Cupedidae ( Archostemata )(=Cupesidae), Micromalthidae (Archostemata), Buprestidae (Buprestidea) ( including Schizopodidae ), Zopheridae (Tenebrionidae) ( including Merycidae), Cerambycidae (Chrysomeloidae) ( including Disteniidae, Hypocephalidae, Oxypeltidae, Parandridae, Spondylidae, Vesperiidae ). In F. W. Stchr (Ed.), Immature insects, (vol. 2, p. 298–302, 386–388, 518–519, 556–561). Dubuque: Kendall/Hunt Publishing Co.Google Scholar
- Lawrence, J. F., Beutel, R. G., Leschen, R. A., & Slipinski, A. (2010). 2.Glossary of morphological terms. Band 4:Pp.9-20. In R. A. B. Leschen, R. G. Beutel, & J. F. Lawrence (Eds.), Handbook of zoology. Vol.IV Arthropoda: Insecta.Part39. Coleoptera Vol.Google Scholar
- Margarita, I. Y., Kazuki, K., Ryuichiro, M., & Rolf, G. B. (2015). Morphology of the first instar larva of Tenomerga mucida (Chevrolat, 1829 ) (Coleoptera: Archostemata: Cupedidae). Arthropod Systematics & Phylogeny, 73(2), 239–258.Google Scholar
- Matthews, E. G., Lawrence, J. F., Bouchard, P., Steiner, W. E., & Slipinski, S. A. (2010). 11.14 Tenebrionidae Latreille, 1802. In R. A. B. Leschen, R. G. Beutel, & J. F. Lawrence (Eds.), Handbook of zoology, a natural history of the phyla of the animal Kingdom.Volume IV- Arthropoda: Insecta. Part 38. Coleoptera, beetles, volume 2: Systematics (Part2).Walter de Gruyter, Berlin: 574–659. 2. New York: Morphology and Systematics (Elateroidea, Bostrichiformia, Cucujiformia partim) Water De Gruyter.Google Scholar
- Newton Jr., A. F. (1991). Agyrtidae (Staphylinoidea), Leiodidae (Staphylinoidea) (= Anisotomidae, Liodidae, including Camiaridae, Catopidae, Cholevidae, Colonidae, Leptodiridae). Sphaeritidae (Hydrophiloidea). Leptinidae (Staphylinoidea) (including Platypsyllidae). Scydmaenidae (Staphylinoidea). Micropeplidae (Staphylinoidea), Dasyceridae (Staphylinoidea), Scaphidiidae (Staphylinoidea), Silphidae (Staphylinoidea). In F. W. Stehr (Ed.), Immature insects, (vol. 2, p. 324–341, 353–355). Dubuque: Kendall/Hunt Publishing Co.Google Scholar
- Ross, D. A., & Pothecary, D. D. (1970). Notes on adults, eggs, and first instar larvae of Priacma serrata (Coleoptera: Cupedidae). Canadian Entomologist, 102, 346–348.View ArticleGoogle Scholar
- Simoes, M. V. P., Quintino, H. Y. S., & Monne, M. L. (2009). Larva and pupa of Nilio(linio) lanatus Germar, 1824 (Coleoptera: Tenebrionidae). Zootaxa, 2175, 51–56.Google Scholar
- Spilman, T. J. (1966). Larva and pupa of Amarygmus morio from Hawaii (Coleoptera: Tenebrionidae). Proceedings of the Hawaiian Entomological Society, XIX, 297–301.Google Scholar
- Spilman, T. J. (1969). Larva and pupa of Pyanisio tristis from Alabama (Coleoptera: Tenebrionidae). The Coleopterists Bulletin, 23(3), 57–61.Google Scholar
- Steiner Jr., W. E. (2014). Larvae and pupae of two north American darkling beetles (Coleoptera, Tenebrionidae, Stenochiinae), Glyptotus cribratus LeConte and Cibdelis blaschkei Mannerheim, with notes on ecological and behavioural similarities. ZooKeys, 415, 311–327.View ArticleGoogle Scholar
- Yi, H., Rolf, G. B., Si, Q. G., Rui, E. N., & Xing, K. Y. (2014). The morphology of galerucine and alticine larvae (Coleoptera: Chrysomelidae) and its phylogenetic implications. Arthropod systematics & phylogeny., 72(2), 75–94.Google Scholar