Paraplea liturata ( Fieber, 1844 )

Nieser, Nico, 2004, Guide To Aquatic Heteroptera Of Singapore And Peninsular Malaysia Iii. Pleidae And Notonectidae, Raffles Bulletin of Zoology 52 (1), pp. 79-96 : 82

Paraplea liturata ( Fieber, 1844)

Ploa liturata Fieber, 1844 .

Plea liturata - Lundblad, 1933 (redescription); Fernando & Cheng, 1974.

Diagnosis. – The small size (length 1.3-1.7 mm) combined with the typical small black dots on the pronotum ( Fig. 1 ) make this species easily recognizable.

Distribution. – India and SE Asia, through Java and Sulawesi to New Caledonia. In West Malaysia recorded from Johor, Melaka, Selangor, Perak and Penang (Fernando & Cheng, 1974).

FAMILY NOTONECTIDAE

Remarks. – Notonectidae or backswimmers is a cosmopolitan family with about 370 species, of which 17 occur in the Malay Peninsula. There are two subfamilies which have different ways of life, to be discussed below. In the Old World the dominant genus of the subfamily Anisopinae is Anisops which has 11 species recorded from the area under consideration. A second genus of Anisopinae , Paranisops , recently discovered in Thailand (Nieser & Zettel, 2001; Chen et al., 2002) might occur also in the Malay Peninsula. The dominant genus of Notonectinae in tropical Asia is Enithares of which four species have been recorded from the Malay Peninsula. Two other genera: Aphelonecta and Nychia , each with one species, are represented in this area.

Most Malayan species of backswimmers are known only in the macropterous form. Only a few species are predominantly brachypterous, but even in those a considerable proportion of the population is able to fly and thereby colonize different kinds of stagnant waters including small pools and puddles and artificial ponds. However, especially in the tropics, some species are more restricted in their habitat choice e.g. most Enithares species and some Anisops are found nearly always in stagnant waters associated with streams or rivers. Fernando & Leong (1976) present locality records for the Malay Peninsula and some notes on habitats.

Notonectidae are strong predators, many species of Notonectinae show strong preference for mosquito larvae and pupae ( Papácek, 2000, 2001). Anisopinae are less frequently reported to attack mosquitoes, perhaps because they usually hunt deeper in the water where they are less likely to encounter mosquito larvae. Several fish prey on backswimmers e.g. Gambusia affinis (Baird & Gerard) ( Miura et al., 1979, 1984) which is sometimes used to control mosquito populations in rice-fields. Notonectidae are relatively scarce or absent from ponds with fish unless there is sufficient marginal vegetation to provide cover (personal observation). Older instars often prey on younger instars of their own species among vegetation, whereas adults tend to stay in the more open water. On the other hand backswimmers can reach considerable densities in cultured fish ponds, preying on the fry, as reported for at least two Malayan species: Anisops bouvieri (Gorai & Chaudhuri, 1962) and A. breddini ( Leong, 1962) .

Figures

Fig. 1. Paraplea liturata length 1.5 mm (simplified from Chen et al., in prep.). cl = clavus; sc = scutellum.