Elaphrothrips

 Fighting males of Elaphrothrips tuberculatus, with a female guarding an egg-mass, from Crespi (1986).

Belongs within: Idolothripinae.

Elaphrothrips is a diverse, primarily pantropical genus of fungus-feeding thrips. Over 100 species are currently recognised in the genus, though some less-studied species may prove to be synonymous (Mound & Palmer 1983).

Thrips wars!
Published 18 February 2014

All around, little dramas are taking place every day, conflicts as intense as the plot of any daytime soap opera. And like most daytime soap operas, the main focus of these dramas often comes down to who is shagging whom. Most people only known thrips as small annoying insects that damage garden plants and crops, but some thrips may engage in remarkable behaviours.

Elaphrothrips is a genus of thrips found almost throughout the tropics (though it is absent from Australasia). They are found on dead leaves, where they feed on fungal spores. Well over a hundred species have been named in Elaphrothrips, though Mound & Palmer (1983) pointed out that many of these may be turn out to be synonymous as individual species can vary significantly in appearance. Males may have thick forelegs with strong tubercles on the femora, while the forelegs of females are usually slender and lack tubercles. Indeed, the sexes are different enough that at one point they have been mistaken for separate genera. The males themselves may vary significantly in size, with larger males having correspondingly larger legs and spines.

A lot of these differences are related to the Elaphrothrips‘ mating behaviour. The best-studied of the Elaphrothrips species is E. tuberculatus, a widespread species in eastern North America and the largest North American thrips species. Elaphrothrips tuberculatus prefer dead oak leaves that are still hanging in clusters from the tree, where females lay eggs in clusters on the leaves and then stand guard over them. The females are themselves guarded by males, but the males may be challenged by others who want to take the female for themselves. Battles between male Elaphrothrips most commonly take the form of the two males lining up alongside each other, as in the drawing at the top of this post, and then one or each begins batting at the other with his elongate abdomen. Alternatively, one male may attempt to reach under his opponent’s abdomen with his own, and then try to flip his opponent over. Crespi (1986) noted that challenging males were more likely to try to flip their opponent than defending males, perhaps because the success rate of flipping attempts was very low, making this tactic more of a gamble. Flipping could also act as a defense against a third attack strategy, in which one male would climb up onto the back of his opponent and use the tubercles on his forelegs to stab at his opponent’s thorax. Larger males were more likely to stab their opponents than smaller males, which of course have less developed leg spines. However, a smaller male may also get around larger male through sneaking behaviour, mating with the female before her guarding male realises he is there.

Whichever male mates with the female, one thing is certain: he will only have daughters. Thrips have a haplodiploid sex determination system like that of ants and bees, with males developing from unfertilised ova and females from fertilised ones. Elaphrothrips tuberculatus adds another wrinkle to the system that only females hatch from eggs. Male offspring, on the other hand, develop inside their mother and are born live (Crespi 1989). Nevertheless, an individual female may have both male and female offspring, as she may change her reproductive mode between broods to be a live-bearer or an egg-layer!

Systematics of Elaphrothrips

Characters (from Mound & Palmer 1983): Large, dark species; head without complex sculpture. Eyes not prolonged ventrally. Fore-ocellus anterior to major ocellar setae. Males with pronotum not produced at anterior angles; fore-femora often with a stout, sickle-shaped seta, without tubercle on inner margin. Abdominal tergites usually with two pairs of major wing-retaining setae (one pair in Elaphrothrips antennalis), larger individuals may have several pairs of supplementary sigmoid setae anterolateral to major pairs. Tube without long lateral setae.

<==Elaphrothrips Buffa 1909MM96 (see below for synonymy)
    |--*E. coniferarum (Pergande 1896) [=Idolothrips coniferarum]MM96
    |--E. acanthomerus Hood 1941MM96
    |--E. addendus Priesner 1928MM96
    |--E. aethiopiae Bagnall 1936MP83
    |--E. affinis (Bagnall 1908) (see below for synonymy)MM96
    |--E. africanus (Trybom 1908) [=Idolothrips africanus]MP83
    |--E. albospinosus Moulton 1929MM96
    |--E. amazonicus Johansen 1979MM96
    |--E. amoenus Priesner 1935MP83
    |--E. andrapterus (Priesner 1932) [=*Elaphridothrips andrapterus]MP83
    |--E. angustatus (Bagnall 1910) [=Idolothrips angustatus]MM96
    |--E. angusticeps (Crawford 1910) [=Idolothrips angusticeps]MM96
    |--E. angustifrons (Bergroth 1888) [=Phloeothrips angustifrons]MM96
    |--E. antennalis Bagnall 1921MP83
    |--E. armatus (Hood 1908) [=Idolothrips armatus]MM96
    |--E. athletes (Karny 1923) [=Kleothrips athletes, E. (*Elaphoxothrips) athletes]MP83
    |--E. aztecus Hood 1941MM96
    |--E. bagnallianus Priesner 1952 [=E. clarispinis Bagnall 1935 non Priesner 1935]MP83
    |--E. bakeri (Karny 1920) (see below for synonymy)MP83
    |--E. bilineatus Priesner 1933MM96
    |--E. blatchleyi Hood 1938MM96
    |--E. borgmeieri Hood 1955MM96
    |--E. bottegii (Buffa 1909) [=Dicaiothrips bottegii]MP83
    |--E. brachypes Bagnall 1934 [incl. E. jeanneli Bagnall 1935]MP83
    |--E. brachyurus Bagnall 1926MP83
    |--E. brasiliensis Johansen 1979MM96
    |--E. breviceps (Bagnall 1921) [=Dicaiothrips breviceps]MP83
    |--E. brunneipennis Bagnall 1935MP83
    |--E. capensis Faure 1942MP83
    |--E. carayoni Bournier 1971MP83
    |--E. championi (Bagnall 1910) [=Dicaiothrips championi]MM96
    |--E. cognatodampfi Johansen 1980MM96
    |--E. cognatograndis Johansen 1978MM96
    |--E. congoensis Priesner 1932MP83
    |--E. conicurus Bagnall 1934MM96
    |--E. coniger Priesner 1952 [=E. (*Paraclinothrips) coniger; incl. E. coniger f. gynaecoides Priesner 1952]MP83
    |--E. constrictopeltatus Johansen 1979MM96
    |--E. coreanus Woo 1974MP83
    |--E. costalimai Hood 1955MM96
    |--E. curvipes Priesner 1929 [incl. E. karnyi Priesner 1935, E. secus Ananthakrishnan 1973]MP83
    |--E. dampfi Hood 1940MM96
    |--E. decipiens Priesner 1932MP83
    |--E. defectus Hood 1941MM96
    |--E. denticollis (Bagnall 1909) (see below for synonymy)MP83
    |--E. devius Priesner 1952MP83
    |--E. distans Bagnall 1935MP83
    |--E. drepanatus (Priesner 1927) [=Dicaiothrips drepanatus]MP83
    |--E. drepanifer (Faure 1925) [=Dicaiothrips drepanifer]MP83
    |--E. edouardi Jacot-Guillarmod 1939MP83
    |--E. falcatus (Karny 1912) [=Dicaiothrips falcatus]MP83
    |--E. fallax Priesner 1952MP83
    |--E. faurei Jacot-Guillarmod 1939MP83
    |--E. femoralis (Bagnall 1918) [=*Klinothrips femoralis]MP83
    |--E. flavipes (Hood 1908) [=Idolothrips flavipes]MM96
    |--E. foveicollis (Bagnall 1908) [=Idolothrips foveicollis; incl. Dicaiothrips grandis Bagnall 1910]MM96
    |--E. fulmeki Priesner 1935MP83
    |--E. gaboniensis Bagnall 1936MP83
    |--E. garciaaldretei Johensen 1980MM96
    |--E. genaspinosus Moulton 1928MP83
    |--E. gnidiicolus (Hesse 1934) [=Dicaiothrips gnidiicolus]MP83
    |--E. gracilis Moulton 1933MM96
    |--E. gravis Priesner 1952MP83
    |--E. greeni (Bagnall 1914) (see below for synonymy)MP83
    |--E. herculeus Johansen 1980MM96
    |--E. herricki Moulton 1933MM96
    |--E. impensus Morrison 1958MP83
    |--E. indigator Hood 1936MM96
    |--E. insignis Ananthakrishnan 1973 [=E. (*Cradothrips) insignis]MP83
    |--E. insperatus Johansen 1979MM96
    |--E. insularis Priesner 1928MP83
    |--E. jacobsoni Priesner 1935MP83
    |--E. jacotguillarmodi Johansen 1979MM96
    |--E. laevicollis (Bagnall 1910) [=Dicaiothrips laevicollis]MM96
    |--E. laticeps Bagnall 1935MP83
    |--E. laticornis Jacot-Guillarmod 1941MP83
    |--E. lewisi Johansen 1980MM96
    |--E. longiceps (Bagnall 1908) [=Idolothrips longiceps]MM96
    |--E. longispinis Priesner 1932MP83
    |--E. mabirensis (Priesner 1925) [=Dicaiothrips mabirensis]MP83
    |--E. macateei Hood 1955MM96
    |--E. madagascariensis Bagnall 1935MP83
    |--E. magnus Johansen 1979MM96
    |--E. mahensis (Bagnall 1921) [=Dicaiothrips mahensis; incl. D. hystrix Bagnall 1921, D. rex Bagnall 1921]MP83
    |--E. malayensis (Bagnall 1909) (see below for synonymy)MP83
    |--E. mantoideus Girault 1927 [=Elaphothrips (l. c.) mantoideus]G27
    |--E. maya Johansen 1986MM96
    |--E. maynei Priesner 1932MP83
    |--E. medius Hartwig 1948MP83
    |--E. microacanthomerus Johansen 1979MM96
    |--E. morelensis Johansen 1980MM96
    |--E. neodampfi Johansen 1979MM96
    |--E. neoleonensis Johansen 1979 (see below for synonymy)MM96
    |--E. neolongiceps Johansen 1979MM96
    |--E. niger Jacot-Guillarmod 1937MP83
    |--E. nigricornis (Karny 1912) [=Idolothrips nigricornis]MP83
    |--E. nigripes Jacot-Guillarmod 1937MP83
    |--E. nitidus (Bagnall 1910) [=Dicaiothrips nitidus]MM96
    |--E. notabilis Ananthakrishnan 1973MP83
    |--E. oaxacaensis Johaansen 1980MM96
    |--E. occidentalis Johansen 1980MM96
    |--E. oculatoides Priesner 1932MP83
    |--E. oculatus Moulton 1928MP83
    |--E. orangiae Jacot-Guillarmod 1937MP83
    |--E. palustris (Hood 1952)MM96 [=*Palinothrips palustrisMP83]
    |--E. paradampfi Johansen 1979MM96
    |--E. parallelus Hood 1924MM96
    |--E. parvus Priesner 1936MP83
    |--E. peruviensis Hood 1936MM96
    |--E. powelli Jacot-Guillarmard 1937MP83
    |--E. priesneri Bagnall 1926MM96 [=Dicaiothrips breviceps Priesner 1921 non Bagnall 1921MP83]
    |--E. procer (Schmutz 1913) (see below for synonymy)MP83
    |--E. propeherculeus Johansen 1980MM96
    |--E. propinquus (Bagnall 1910)MM96 (see below for synonymy)
    |--E. prospector Hood 1936MM96
    |--E. pseudotuberculatus Johansen 1980MM96
    |--E. schotti (Heeger 1852)MM96 [=Thrips schottiMM96, *Dicaiothrips schottiiMP83]
    |--E. schoutedeni Priesner 1932MP83
    |--E. schultzei Priesner 1933MM96
    |--E. sensitivus Priesner 1929MP83
    |--E. separatus Priesner 1928MP83
    |--E. seychellensis (Bagnall 1921) [=Dicaiothrips seychellensis]MP83
    |--E. snodgrassi Hood 1955MM96
    |--E. spiniceps Bagnall 1932 [incl. E. clarispinis Priesner 1935, E. graveleyi Bagnall 1934]MP83
    |--E. spiniprivus Priesner 1952MP83
    |--E. spinosus Moulton 1933MM96
    |--E. stenocephalus (Bagnall 1914) (see below for synonymy)MP83
    |--E. surinamensis Priesner 1925MM96
    |--E. tener Priesner 1925MM96
    |--E. tepotzlanensis Johansen 1986MM96
    |--E. transvaalensis Jacot-Guillarmod 1939MP83
    |--E. tuberculatus (Hood 1908) [=Idolothrips tuberculatus]MM96
    |--E. unicolor Moulton 1933MM96
    |--E. uniformis Buffa 1909MP83
    |--E. villai Johansen 1980MM96
    |--E. vittipennis Hood 1940MM96
    |--E. zacualtipanensis Johansen 1983MM96
    `--E. zetetis Hood 1936MM96

Elaphrothrips Buffa 1909MM96 [=Elaphothrips (l. c.)G28; incl. Cradothrips Ananthakrishnan 1973MP83, Dicaiothrips Buffa 1909MP83, Elaphoxothrips Bagnall 1932MP83, Elaphridothrips Priesner 1932MP83, Klinothrips Bagnall 1918MP83, Palinothrips Hood 1952MP83, Paraclinothrips Priesner 1952MP83]

Elaphrothrips affinis (Bagnall 1908) [=Idolothrips affinis; incl. I. assimilis Bagnall 1908, Dicaiothrips distinctus Bagnall 1910]MM96

Elaphrothrips bakeri (Karny 1920) [=Dicaiothrips bakeri; incl. E. bakeri var. depokensis Priesner 1935, E. imitator Priesner 1935, E. mentaweiensis Priesner 1929]MP83

Elaphrothrips denticollis (Bagnall 1909) [=Dicaiothrips denticollis; incl. E. beesoni Ramakrishna 1934, E. mucronatus Priesner 1935, E. productus f. obscuricornis Priesner 1935, E. productus Priesner 1935, E. sumbanus Priesner 1935]MP83

Elaphrothrips greeni (Bagnall 1914) [=Dicaiothrips greeni; incl. D. bouvieri Vuillet 1914, Elaphrothrips micidus Ananthakrishnan 1973]MP83

Elaphrothrips malayensis (Bagnall 1909) [=Dicaiothrips malayensis; incl. D. bruneitarsis Schmutz 1913, Elaphrothrips coronatus Bagnall 1934, D. bruneitarsis var. levis Schmutz 1913]MP83

Elaphrothrips neoleonensis Johansen 1979 [incl. E. bagnalli Johansen 1980, E. guachichilis Johansen 1979, E. lacandonis Johansen 1980]MM96

Elaphrothrips procer (Schmutz 1913) [=Dicaiothrips procer; incl. E. achaetus Bagnall 1934, E. approximatus Bagnall 1934, E. chandana Ramakrishna 1934, Dicaiothrips dallatorensis Schmutz 1913, E. eranthemi Seshadri & Ananthakrishnan 1954, D. novus Schmutz 1913, D. proximus Bagnall 1914]MP83

Elaphrothrips propinquus (Bagnall 1910)MM96 [=Dicaiothrips propinquusMM96; incl. D. brevicornis Bagnall 1910MM96, Elaphrothrips brevicornisMP83]

Elaphrothrips stenocephalus (Bagnall 1914) [=Dicaiothrips stenocephalus; incl. E. atrispinus Bagnall 1935, E. nigrospinosus Bagnall 1932, E. variispinis Bagnall 1935]MP83

*Type species of generic name indicated

References

Crespi, B. J. 1986. Size assessment and alternative fighting tactics in Elaphrothrips tuberculatus (Insecta: Thysanoptera). Animal Behaviour 34: 1324–1335.

Crespi, B. J. 1989. Facultative viviparity in a thrips. Nature 337: 357–358.

[G27] Girault, A. A. 1927. A discourse on wild animals. Privately published (reprinted: Gordh, G., A. S. Menke, E. C. Dahms & J. C. Hall. 1979. The privately printed papers of A. A. Girault. Memoirs of the American Entomological Institute 28: 216–217).

[G28] Girault, A. A. 1928. Some Insecta and a new All Highness. Privately published (reprinted: Gordh, G., A. S. Menke, E. C. Dahms & J. C. Hall. 1979. The privately printed papers of A. A. Girault. Memoirs of the American Entomological Institute 28: 225–228).

[MM96] Mound, L. A., & R. Marullo. 1996. The thrips of Central and South America: an introduction (Insecta: Thysanoptera). Memoirs on Entomology, International 6: 1–487.

[MP83] Mound, L. A., & J. M. Palmer. 1983. The generic and tribal classification of spore-feeding Thysanoptera (Phlaeothripidae: Idolothripinae). Bulletin of the British Museum (Natural History): Entomology series 46 (1): 1–174.

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