Biology of Newly Recorded Predator Antilochus coquebertii of Red Cotton Bug, Dysdercus koenigii Fabricius (Hemiptera: Pyrrhocoridae) from Pakistan

Exploratory searches were made by the Central Cotton Research Institute (CCRI), Multan Pakistan, to collect D. koenigii and its natural enemies from different districts of Pakistan, in order to address this problem. As a result of these searches, we recorded for the first time A. coquebertii from D. koenigii infested cotton fields of Cotton Research Station (CRS), Rata Kulachi (30’ 15” 32’ 17” N 70’ 11” 70’ 42”E) District Dera Ismail Khan, Ali Pur (32°56′00″N 73°13′00″E) District Muzafar Garh and Bahauddin Zakariya University Multan (30°11′52″N 71°28′11″E), Pakistan in 2012. A. coquebertii specimens were collected in plastic jars and brought back to the CCRI Entomology lab and efforts were made for its rearing. Voucher specimens have been deposited in laboratory of the Entomology Section of CCRI, Multan, Pakistan.

Plastic cages measuring 37.5 × 22.5 × 37.5 cm (L × W × D) having three aeration holes (7.5 ×7.5 cm) covered with fine mesh were used to rear A. coquebertii in the laboratory conditions (27±2ºC, 60-75% RH, 11L: 13D photoperiod). To provide substratum for oviposition, the floor of plastic cage was covered with one inch layer of sterilized soil and sand, and dry leaves with twigs of cotton crop were kept inside the cage. Petri dishes (5cm) having moistened cotton covered with filter paper were placed in the cage to maintain moisture. D. koenigii were provided as food on daily basis. To study the survival and the developmental period for each nymphal instar of A. coquebertii, 25 newly emerged instars were placed individually in plastic cups (10×10 cm) that were half filled with sterilized soil mixed with sand, and soaked cotton was placed on the soil. Every day, D. koenigii (3rd-5th instar) were provided as food in plastic cups individually. Five newly emerged pairs of A. coquebertii were placed individually in plastic cups to record reproductive biology.

A. coquebertii are oval, elongate, and resembles to D. koenigii with the following differences. A. coquebertii have narrow black transverse lines on ventral abdominal side of nymphs and adults are bright red in colour without any black spot on wings. By contrast D. koenigii nymphs and adults have white lines on ventral side of abdomen and adults are crimson red in colour having black spots on scutellum.

A. coquebertii has five nymphal instars. Among the nymphal instars, developmental period of 1st, 2nd, 3rd and 4th instars was 6.8, 5.2, 7.4 and 7.8 days, respectively at 27±2ºC along with 60-75% RH. These instars consumed 6-7, 3-13, 3-17, 7-10 and 11-19 numbers of preys, respectively. Developmental period of 5th instar A. coquebertii was longer (15days) but its survival percentage was lower (54%) than other instars with consumption of approximately 30-66 prey (Table I). Total nymphal developmental period was 42.1±1.18 days. Female laid eggs on soil under leaves or in cracks in batches with an average of 61±6.82 eggs/ batch (Table II).

D. koenigii is difficult to control in the field due to rapid reproduction, high mobility and wide host range (Jalil et al., 2013; Kohno, 2003). Therefore, the use of the biocontrol -agent A. coquebertii to control D. koenigii should be considered because it can tolerate temperatures typical of tropical and subtropical regions (Kohno, 2003) and further the use of biocontrol-agents may be applicable not only to cultivated cotton fields, but also to wild alternative hosts. Red cotton bug appears usually at squaring and boll formation stage of cotton (our personal observation). Transgenic cotton needs pesticides only for sucking insect pests like jassid, Amrasca devastans (Dist.) and whitefly, Bemisia tabaci (Genn). Toxic impact of insecticides like imidacloprid, dimethoate etc have been studied for pirate bug, Orius spp. (Hemiptera: Anthocoridae), big eyed bug, Geocoris spp. (Hemiptera: Lygaeidae), green lacewing, C. carnea (Neoroptera: Chrysopidae), lady beetle, Coccinellid spp. (Coleoptera: Coccinellidae) (Saeed et al., 2016). But for Antilochus, impact of insecticides is not yet evaluated in Pakistan. Therefore, further research is needed to evaluate impact insecticides being applied to manage pests of cotton for said predator.

There is dire need to conduct further studies for efficient utilization of A. coquebertii against D. koenigii. Moreover, survey of alternate hosts of both the D. koenigii and A. coquebertii is also required to determine their role in harbouring pest and natural enemies. As alternate host plants may be beneficial in terms of providing alternate food source to natural enemies or detrimental being food reservoir for the pest (Saeed et al., 2015a, b).

The authors declare there is no conflict of interest.