METAPARASITYLENCHUS HYPOTHENEMI N. SP. (NEMATODA: ALLANTONEMATIDAE), A PARASITE OF THE COFFEE BERRY BORER, HYPOTHENEMUS HAMPEI (CURCULIONIDAE: SCOLYTINAE)

Metaparasitylenchus hypothenemin. sp. (Nematoda: Allantonematidae) is described from the coffee berry borer, Hypothenemus hampei(Ferrari) (Curculionidae: Scolytinae), in Chiapas, Mexico. This species differs from other members of the genus by its small size, annulated cuticle, lateral fields with 3 ridges, free-living stages with an excretory pore located between the pharyngeal gland orifices, a distinct stylet with basal swellings in free-living females, a postvulval uterine extension, a thin stylet lacking basal swellings in males, 2 separate spicules, a gubernaculum, and a peloderan bursa. Parasitic females are white, with a straight or slightly curved body and are ovoviviparous. Third-stage juveniles emerge from parasitized beetles and molt twice before reaching the adult stage. Because the coffee berry borer is the most important pest of coffee throughout the world and this parasite partially or completely sterilizes female beetles, it is worthy of further investigation as a potential biological control agent. The coffee berry borer (Hypothenemus hampei (Ferrari) (Curculionidae: Scolytinae)) is the most important pest of cof- fee in the world (Le Pelley, 1968). Because most of the life history of the beetle occurs within the protected confines of the coffee berry, standard chemical control methods have, for the most part, been unsuccessful (Bustillo et al., 1998), with resis- tance arising against the most commonly used insecticide, en- dosulfan (Brun et al., 1989). As a result, alternative biological control methods are being investigated, including the use of pathogens and parasitoids to be included in pest management strategies against the coffee berry borer. During studies on the biology of the coffee berry borer in field plantations in the municipality of Cacahoatan, Chiapas, parasitic nematodes were discovered in the body cavity of adult beetles (Fig. 9) and tentatively assigned to Sphaerulariopsis (Castillo et al., 2002). The presence of the excretory pore an- terior to the nerve ring, males with well-developed stylets, ce- phalated spicules, a gubernaculum, and a large peloderan bursa, together with elongate-tuboid parasitic females, places the pre- sent species in Metaparasitylenchus Wachek 1955 (Siddiqi, 2000). Because the specimens differ from all previously de- scribed species in the genus (Wachek, 1955; Siddiqi, 2000), they are described below as a new species. MATERIALS AND METHODS Although over 200 infected hosts were examined during this inves- tigation, the description was based on nematodes obtained from 10 lar- vae, 7 pupae, and 20 adult beetles. Nematodes (third-stage juveniles) that emerged from the body cavity of adult beetles were placed in hang- ing-drop slides (H2O) and observed daily during a 2-wk period. The hanging-drop slides were placed in separate petri dishes containing wet filter paper to retard drying and held at 20 C. During this time, the nematodes matured and molted to the adult stage. Observations and photographs were made with living as well as fixed nematodes using a Nikon Optiphot Microscope. Measurements were made on nematodes that had been killed in hot (60 C) water, fixed in TAF, and processed to glycerin by the evaporation method. All measurements, including the average value and those of the range (in parentheses), are in micro- meters unless otherwise specified.