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Mordellidae

The Mordellidae are a family of beetles commonly known as tumbling flower beetles for the typical irregular movements they make when escaping predators, or as pintail beetles due to their abdominal tip which aids them in performing these tumbling movements.[citation needed] Worldwide, there are about 1500 species.[1]

Mordellidae
Temporal range: Middle Jurassic–Recent
Mordella aculeata; note the "pintail"
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Suborder: Polyphaga
Infraorder: Cucujiformia
Superfamily: Tenebrionoidea
Family: Mordellidae
Latreille, 1802
Subfamilies
Synonyms

Liaoximordellidae

Anatomy

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The apparent tumbling movements are composed of a series of very rapid separate jumps (each jump of a duration of approximately 80 ms). They result from the beetle's efforts to get itself back into take-off position for flight when it has been in either a lateral or dorsal position. Each individual jump should be considered an extended rotation, performed by one leg of the third leg pair (metapodium). Depending on whether the left or the right metapodium is used as the leg that provides the leverage for take-off, change occurs in the direction of the jump. The energy for propulsion varies with the beetle's immediate muscle work, so that jump lengths and heights vary, with rotation frequencies recorded up to 48 per second (Mordellochroa abdominalis) around the gravitation centre of the body's longitudinal axis. Additional revolving around the transverse axis (at lower frequency) effects spiralling somersaults that are perceived as tumbling. While the pintail (pygidium) is of no significance for the jump, the meta-trochanter-femur (thighs and surrounding rings of the third leg pair) has a great capacity for free rotation (up to 270 degrees, at one level only). This capacity is due to a screw joint that connects the base of the metacoxa to the head of trochanter. The nut gradient is 21 degrees. Technically similar jumps, though less powerful, can be observed in the families Melandryidae (=Serropalpidae) (genus Orchesia) and Scraptiidae (genus Anaspis). Their coxa-trochanter-joints are of similar structure. It is inferred that the capacity of a tumbling form of locomotion is rooted in a common phylogeny and can therefore not be ascribed specifically to Mordellidae.[2] Other authors have pointed out the speciality of the screw joint. Weevils of the genus Trigonopterus, in the Asian tropical rainforest, for example, have an even tighter connective construction in the coxa-trochanter joint than is found in Mordellidae. This construction, however, does not facilitate an equally high angular velocity of the torque. The joint here serves to provide a better grip on plants and easier climbing.[3]

Systematics

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Adult Tomoxia lineella (Mordellinae: Mordellini)
 
Larva of Mordellistena sp. (Mordellinae: Mordellistenini) larva inside a goldenrod gall made by the fly Eurosta solidaginis
 
Adult female Tolidopalpus nitidicoma (Mordellinae: Mordellistenini) from side
Mating tumbling flower beetles in a morning glory flower.
Tumbling flower beetles on a daisy

This family has two living subfamilies – Mordellinae and Ctenidiinae – and a prehistoric one known only from fossils (Praemordellinae).[4] Another fossil genus, Liaoximordella, was previously treated as distinct monotypic family Liaoximordellidae, but is now regarded as very primitive and probably basal member of the Mordellidae.

Subfamily Ctenidiinae Franciscolo, 1951

Subfamily Mordellinae Latreille, 1802

References

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  1. ^ Michael A. Ivie (2002). "Mordellidae". In Ross H. Arnett & Michael Charles Thomas (ed.). Polyphaga: Scarabaeoidea through Curculionoidea. American Beetles. Vol. 2. CRC Press. ISBN 978-0-8493-0954-0.
  2. ^ Michael Reuter (1995). "Studies on the functional morphology of the jump in tumbling-flower beetles (Mordellidae, Coleoptera)". Acta Biologica Benrodis. 7: 99–133. ISSN 0177-9214.
  3. ^ Van De Kamp, T.; Vagovic, P.; Baumbach, T.; Riedel, A. (2011). "A Biological Screw in a Beetle's Leg". Science. 333 (6038): 52. Bibcode:2011Sci...333...52V. doi:10.1126/science.1204245. PMID 21719669.
  4. ^ Mordellidae Species List at Joel Hallan's Biology Catalog. Texas A&M University, archived from the original on 7 October 2014, retrieved 8 August 2015
  5. ^ Horák, Jan; Farkac, Jan; Nakládal, Oto (2012). "Mordellidae (Coleoptera) from Socotra Island" (PDF). Acta Entomologica Musei Nationalis Pragae. 52 (supplementum 2): 253–268. ISSN 0374-1036. Retrieved 5 February 2013.
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