Chilocorus Leach

POORANI, J., 2023, An illustrated guide to the lady beetles (Coleoptera: Coccinellidae) of the Indian Subcontinent. Part II. Tribe Chilocorini, Zootaxa 5378 (1), pp. 1-108 : 32

Genus Chilocorus Leach

( Fig. 22 )

Chilocorus Leach , in Brewster 1815: 116. Type species: Coccinella cacti Linnaeus, 1767: 584 , by monotypy.

Anisorcus Crotch, 1874: 190 . Type species: Anisorcus fryi Crotch, 1874: 191 , by original designation. Synonymized by Li et al. 2020b: 461.

Egius Mulsant, 1850: 464 . Type species: Egius platycephalus Mulsant, 1850: 464 , by monotypy. Synonymized by Li et al. 2020b: 461.

Phaenochilus Weise, 1895a: 135 . Type species: Phaenochilus punctifrons Weise, 1895a: 136 , by subsequent designation of Korschefsky 1932. Synonymized by Li et al. 2020b: 461.

Simmondsius Ahmad & Ghani, 1966: 9 . Type species: Simmondsius pakistanensis Ahmad & Ghani, 1966: 9 , by original designation. Synonymized by Li et al. 2020b: 461.

Diagnosis. Form broadly oval to almost circular or distinctly apically narrowed; dorsum hemispherical, dome-like and strongly convex, usually shiny and glabrous, only head and sides of pronotum with hairs ( Fig. 22a ). Antennae ( Fig. 22b ) with 7–8 antennomeres, last antennomere as long as or distinctly longer than penultimate one. Clypeus long, laterally extending into eyes. Frons usually wide, but narrow and distally tapering in some species (erstwhile members of Phaenochilus , now subsumed into Chilocorus ). Terminal maxillary palpomere with subparallel sides ( Fig. 22c ), narrowing towards obliquely truncate apex or slender and elongate, parallel-sided and apically narrowed (in erstwhile members of Phaenochilus ). Prosternal lobe flat and broad, without carinae ( Fig. 22d ). Terminal labial palpomere subconical or elongate, slender, and rodlike (erstwhile Phaenochilus ). Elytral epipleuron strongly descending externally, foveolate on level with middle and hind legs. Abdomen with six visible ventrites in male and five in female, rarely six in both. Abdominal postcoxal line incomplete, running parallel to and apically merging with posterior margin of first abdominal ventrite. Legs with stout femora; tibiae flattened and externally angulate, with a triangular projection on outer margin a little before middle ( Fig. 22e ); tibial spurs absent. Tarsal claws strongly curved and appendiculate (except in C. pakistanensis ( Ahmad & Ghani, 1966) [= Simmondsius pakistanensis ], in which clawas are weakly sickle-shaped / falciform with reduced basal teeth). Male genitalia ( Fig. 22g –j ) with penis guide apically symmetrical ( Fig. 22h ) or asymmetrical, parameres often densely setose ( Fig. 22g ). Coxites elongate triangular or transverse. Cornu of spermatheca invariably with a distal projection ( Fig. 22f ). Infundibulum absent.

Distribution. This genus is the largest of the tribe Chilocorini and is cosmopolitan in distribution.

Affinities. In the phylogenetic analyses done by Li et al. (2020b), Chilocorus was recovered in a clade comprising Renius Li & Wang. Li et al. (2020b) recovered four other genera, Simmondsius Ahmad & Ghani , Phaenochilus Weise , Egius Mulsant , and Anisorcus Crotch , in the same clade along with Chilocorus and synonymized them and redefined the generic concept of Chilocorus .

Biology. Members of Chilocorus are primarily predatory on Coccoidea, especially armoured scales ( Diaspididae ), soft scales ( Coccidae ), and more rarely on mealybugs ( Pseudococcidae ). They also feed on aphids and adelgids ( Belicek 1976; Gordon 1985), psyllids ( Husain & Nath 1927), and whiteflies ( Kapur 1940).

Many species of Chilocorus are economically important as they are widely used as biological control agents ( Ślipiński & Giorgi 2006), such as Chilocorus nigrita ( Fabricius, 1798) , which is widely distributed due to its deliberate introduction for biological control ( Booth 1998).

Included species. Chilocorus is the largest genus of this tribe from the Indian subcontinent and 16 species are known from mainland India at present (including those transferred from Phaenochilus and Simmondsius , as these two genera are now considered as synonyms of Chilocorus as per the current generic classification). ‘ Egius sp. ’ was reported from the state of Uttarakhand ( Chakraborty 2010) and the identity of this species could not be verified.

The following works may be consulted for more details on the Chilocorini of the Indian subcontinent : Nagaraja & Hussainy 1967 (review of Chilocorus species predatory on San Jose scale, including introduced ones); Miyatake 1970a (review of some Chilocorini of Asia); Booth 1998 (review of the Chilocorus nigrita species complex from the Oriental region); Giorgi & Vandenberg 2012 (review of the genus Phaenochilus , including the two Indian species); Li et al. 2018 (review and illustrations of Chinese Chilocorus , including some Indian species; a world checklist of Chilocorus ).

Figures

FIGURE 22. Chilocorus nigrita (Fabricius): a. adult; b. antenna; c. maxilla; d. prosternum; e. hind leg; f. spermatheca; g–j. male genitalia: g. tegmen, lateral view; h. tegmen, ventral view; i. penis; j. penis apex.