Lyttini

Lydus europaeus, copyright Luca Boscain.

Belongs within: Meloinae.
Contains: Lytta.

Associating with the Spanish fly
Published 12 December 2023

The classification of the blister beetles has been subject to numerous revisions over the years, with the status of many subgroups remaining uncertain. Perhaps the most uncertainty of all has surrounded the representatives of the tribe Lyttini.

Lydus trimaculatus, copyright Kostas Zontanos.

As a tribe of the subfamily Meloinae, the Lyttini have historically been united by features of the first instar larvae. Like most other blister beetles, lyttins begin their lives as parasites or kleptoparasites on other insects. They exhibit hypermetamorphy where the first larval instar (the triungulin) is distinct from later stages and adapted to seek out the nests of hosts. In some blister beetles, the triungulins are adapted for phoresy, hitching a ride on a larger insect to reach their host, but the newborn larvae of Lyttini lack such adaptations and must find their host by more active means. Lyttin triungulins are united by antennae with a long terminal seta, more than twice as long as the antenna itself. In most species, the abdomen lacks laterotergites and the spiracles are placed dorsally (Bologna & Pinto 2001). The hosts of Lyttini, where known, are usually bees though the southern African Australytta are associated with eumenine wasps (Bologna & Pinto 2002).

Triungulin larva of Teratolytta gentilis, from Riccieri et al. (2022).

In contrast to the fairly uniform larvae, however, adult Lyttini are structurally diverse and lack distinct unifying features. As such, it was not entirely surprising when a molecular phylogenetic analysis of the tribe by Riccieri et al. (2022) established found that the ‘lyttins’ were not monophyletic. Instead, Riccieri et al. found evidence of no less than eleven deeply divergent lineages interspersed alongside representatives of other tribes (and while they did not include any of the Neotropical ‘lyttins’, they noted that their distinctive appearance suggested that they too were not related to the core assemblage around the type genus Lytta). The implication is that the supposed ‘lyttin’ larva is potentially plesiomorphic for the Meloinae as a whole or a convergent adaptation to similar host relationships. Riccieri et al. (2022) suggested that the Lyttini should be restricted to a clade of five genera found in the Holarctic realm but did not describe what (if any) morphological features were characteristic of this clade.

Spanish fly Lytta vesicatoria, copyright Siga.

Whatever its circumscription, there is no question that the most notorious representative of the Lyttini is its type species Lytta vesicatoria, the beetle commonly referred to as the ‘Spanish fly’. This bright, metallic green beetle is widespread in the western Palaearctic, being particularly abundant in southern Europe. It is best known for the production of the defensive chemical cantharidin which, like other blister beetles, it exudes in a fluid from its mouth and joints as a defense against predators. This substance is highly toxic, causing blistering and bleeding from mucous tissues, and its ingestion has been implicated in more than one human death. Nevertheless, it also has a long history of being thought to have aphrodisiac properties, perhaps by people who took the expression ‘burning loins’ a little too literally. According to Wikipedia, It has even been used for culinary purposes, with crushed beetles an ingredient in certain variations of the Moroccan spice mix ras el hanout. Supposedly, however, the use of this component has been disallowed in recent decades, so while your ras el hanout may indeed be spicy, you can feel a bit more reassured that it is unlikely to be lethal.

Systematics of Lyttini
Lyttini
|--+--Muzimes Aksentjev 1988RM22, BP02 [=Micromerus Mulsant & Rey 1858 non Rambur 1842BP02]
| | |--*M. collaris (Fabricius 1787)BP02 (see below for synonymy)
| | |--M. caucasicusRM22
| | `--M. sterbai (Maran 1941)BP02
| `--Pseudolytta Selander 1960RM22, BP02
| |--*P. aeneiventris (Haag-Rotenberg 1880) [=Lytta aeneiventris]BP02
| |--P. kwanshiensis [=Lytta kwanhsiensis]RM22
| |--P. spissicornis [=Lytta spissicornis]RM22
| `--P. taliana [=Lytta taliana]RM22
`--+--LyttaRM22
`--Alosimus Mulsant 1857RM22, BP02 [=Halosimus Gemminger & Harold 1870BP02]
|--+--*A. syriacus (Linnaeus 1758)BP02, RM22, BP02 [=Meloe syriacusBP02]
| `--+--A. cirtanusRM22
| `--A. mendaxRM22
`--+--+--+--A. armeniacus (Faldermann 1837)RM22, BP02
| | `--A. longicollisRM22
| `--+--A. robustusRM22
| `--A. viridissimusRM22
`--+--+--A. sulcicollisRM22
| `--+--A. decolorRM22
| `--A. luteusRM22
`--Lydus Dejean 1821RM22, BP02 [Lydina]
| i. s.: L. impressicollis Fairmaire 1892 [=Syriolytta impressicollis]BP02
|--+--L. praeustusRM22
| `--+--L. humeralisRM22
| `--L. tarsalisRM22
`--+--+--+--*L. algiricus (Linnaeus 1758)BP02, RM22, BP02 [=Meloe algiricusBP02]
| | `--+--L. marginatus (Fab. 1792)RM22, BP02
| | `--L. sanguinipennisRM22
| `--+--+--L. europaeusRM22
| | `--L. italicus [=L. trimaculatus italicus]RM22
| `--+--L. tenuitarsusRM22
| `--+--L. unicolorRM22
| `--+--L. trimaculatus (Fabricius 1775)RM22, BP02
| `--L. turcicusRM22
`--Oenas Latreille 1802RM22, BP02
| i. s.: ‘Aenas’ bicolor Laporte de Castelnau 1840LC40
| ‘Aenas’ nigricollisLC40
| O. ruficollis Olivier 1811G-PR05
| ‘Aenas’ unicolor Laporte de Castelnau 1840LC40
| ‘Aenas’ wilhelmsiiLC40
|--O. fusicornis Abeille de Perrin 1880RM22, G-PR05 [incl. O. hispanus Abeille de Perrin 1880G-PR05]
`--+--+--O. brevicollisRM22
| `--O. tarsensisRM22
`--+--O. crassicornis (Illiger 1800)RM22, G-PR05
`--+--O. afer (Linnaeus 1758)RM22, G-PR05 (see below for synonymy)
`--O. sericeus (Ol. 1795)RM22, BP02

Lyttini incertae sedis:
Pseudosybaris Saha 1982BP02
`--*P. kempi Saha 1982BP02
Afrolytta Kaszab 1959BP02
|--*A. carneola (Péringuey 1892) [=Lytta carneola]BP02
`--A. amoena (Per. 1892)BP02
Eolydus Denier 1913BP02
|--E. atripes (Pic 1905) [=Alosimus atripes; incl. *E. atrocoeruleus Denier 1913]BP02
|--E. afghanicusBP02
`--E. conspicuus (Waterhouse 1889)BP02
Sybaris Stephens 1832 [incl. Prionotus Redetenbacher 1842 nec Lacépède 1801 nec Hisinger 1837]BP02
|--*S. immunis Stephens 1832BP02
|--S. ictericus (Gyll. 1817)BP02
`--*Prionotus’ praestus Redtenbacher 1842BP02
Lydulus Semenov 1893 [incl. Lydoenas Reitter 1894]BP02
|--*L. albopilosus Semenov 1893BP02
|--‘Lydus’ pygmaeus Dokthouroff 1890 [=*Lydoenas pygmaeus]BP02
|--L. semipurpureus Reitter 1902BP02
`--L. uzbekistanus Kaszab 1981BP02

Nomen nudum: Oenas villiger Salvañá Comas 1870G-PR05

*Muzimes collaris (Fabricius 1787)BP02 [=Litta (l. c. for Lytta) collarisBP02, Alosimus collarisG-PR05, Halosimus kollaris (l. c.)G-PR05]

Oenas afer (Linnaeus 1758)RM22, G-PR05 [=Meloe aferBP02; incl. Lytta atrata Latreille 1802 non Fabricius 1775BP02, *Oenas atratusBP02]

*Type species of generic name indicated

References

Bologna, M. A., & J. D. Pinto. 2001. Phylogenetic studies of Meloidae (Coleoptera), with emphasis on the evolution of phoresy. Systematic Entomology 26: 33–72.

[BP02] Bologna, M. A., & J. D. Pinto. 2002. The Old World genera of Meloidae (Coleoptera): a key and synopsis. Journal of Natural History 36 (17): 2013–2102.

[G-PR05] García-París, M., & J. L. Ruiz. 2005. Bibliografía y registros Ibero-Baleares de Meloidae (Coleoptera) publicados hasta la aparición del “Catálogo sistemático geográfico de los coleópteros observados en la Península Ibérica, Pirineos propiamente dichos y Baleares” de J. M. de la Fuente (1933). Graellsia 61 (2): 225–255.

[LC40] Laporte de Castelnau, F. 1840. Histoire Naturelle des Insectes Coléoptères vol. 2. P. Duménil: Paris.

[RM22] Riccieri, A., E. Mancini, M. Pitzalis, D. Salvi & M. A. Bologna. 2022. Multigene phylogeny of blister beetles (Coleoptera, Meloidae) reveals extensive polyphyly of the tribe Lyttini and allows redefining its boundaries. Systematic Entomology 47: 569–580.

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