Micraspis discolor

Micraspis discolor (Fabricius)

(Figs 127–130)

Coccinella discolor Fabricius, 1798: 77 (Lectotype, ZMUC; Type locality: Tranquebar).

Verania discolor: Mulsant, 1850: 369; Korschefsky 1932: 308; Bielawski 1957: 92.

Micraspis discolor: Kamiya 1965b: 60; Sasaji 1968 c: 128; Poorani 2002: 335; Poorani et al. 2023: 450.

Diagnosis. Length: 3.50–5.00 mm; width: 3.00– 3.70 mm. Form (Figs 127a–d, 130m –o) subcircular to oval, dorsum subhemispherical and convex. Ground colour orange yellow with the following markings: Head with a black marking on posterior half reaching up to lower margin of eyes; pronotum with a pair of subtriangular markings along basal margin and two smaller, round spots in middle which are in various states of fusion or absent (Fig. 127e). Antenna yellow, apical antennomeres darker brownish. Scutellar shield very small, triangular. Elytral suture with a thin black stripe. Female genitalia (Fig. 128f–h) and male genitalia (Fig. 128a–d) as illustrated. Variants from northeastern region of India (Fig. 129) are ventrally darker brown but with similar genitalia.

Immature stages. Life stages as illustrated in Fig. 130.

Distribution. India (Assam, Karnataka, Kerala, Meghalaya, Nagaland, Pondicherry, Tamil Nadu); Sri Lanka.

Prey/associated habitat. Hemiptera: Aleyrodidae: Aleurolobus barodensis (Maskell), aleyrodids on sugarcane; Aphididae: Aphis craccivora Koch, Rhopalosiphum nymphaeae (Linnaeus); Cicadellidae: Nephotettix spp.; Delphacidae: Nilaparvata lugens (Stål), Sogatella furcifera (Horvath); Pseudococcidae: Brevennia rehi (Lindinger) (= Ripersia oryzae Green); Lepidoptera: Pyralidae: Egg masses of Scirpophaga incertulas (Walker), early instar larvae of Cnaphalocrocis medinalis (Guenée). Very common on rice; also found on aquatic and semiaquatic vegetation, and sugarcane.

Its role as a predator is rather limited as it feeds on rice pollen and is reported to prefer it to other insect prey. After paddy flowering, it is reported to feed on pollen of weeds and grasses such as Cardanthera balsamica and Echinocloa colona. It is a minor pest during flowering in rice and causes damage by feeding on pollen grains and interferes with grain setting, resulting in chaffy, white grains (Nagaraja Rao & Abraham 1959). However, Afsana & Islam (2001) observed that feeding on rice pollen by even very high populations did not result in grain sterility.

Seasonal occurrence. Collected almost throughout the year. Most abundant, especially during flowering, in rice ecosystem (August, September–October, December.

Notes. Species identified as M. discolor from different parts of Southeast Asia including China and Japan are not conspecific with the nominate form originally described from south India (Tamil Nadu). Poorani et al. (2023) established the identity of M. discolor based on Fabricius’s type material from South India and phylogenetic analysis of the COI sequences of Indian M. discolor and other Asian ‘ M. discolor’ sequences from South and southeast Asian countries also proved it to be a distinct species. Due to the co-existence of more than one species of Micraspis in the rice paddies of the Indian subcontinent, available literature on M. discolor needs to be treated with discretion.