BEHAVIOR OF FEMALE ERETMOCERUS SP NR CALIFORNICUS HOWARD (APHELINIDAE, HYMENOPTERA) ATTACKING BEMISIA-ARGENTIFOLII BELLOWS AND PERRING (ALEYRODIDAE, HOMOPTERA) ON 2 NATIVE CALIFORNIAN WEEDS

Searching and ovipositional behaviors by female Eretmocerus sp. nr. ca lifornicus Howard on Bemisia argenlifolii Bellows and Perring infestin g velvetleaf, Abutilon theophrasti Medic. (Malavaceae), and telegraph weed, Heterotheca grandiflora Nutt. (Asteraceae), were quantified. Adu lt female behaviors were described and quantified for E. sp. nr. calif ornicus to establish a behavioral time budget analysis. Females depart ed from leaves of A. theophrasti in 83.3% of the trials, and of those that remained and searched for hosts, walking speeds averaged 0.29 mm/ s. Females departed from the leaves of H. grandiflora a in 44.4% of th e trials, and those remaining readily searched for whitefly hosts with walking speeds averaging 0.26 mm/s. The duration of host assessment b y antennation was related to subsequent behaviors; rejecting a host wa s a shorter process than accepting it for further evaluation irrespect ive of plant species or nymphal stage. Evidence for a behavioral prefe rence for oviposition under early nymphal instars was documented for f emale E. sp. nr. californicus on both plant species, Oviposition effic iency in l-h laboratory trials for nymphs on A. theophrasti was 30% an d efficiency on H. grandiflora was 23%. Females spent 61.9 and 53.3% o f their total time in searching, host assessment, probing, and oviposi tion while on A. theophrasti and H. grandiflora, respectively. The rem ainder of the time was spent grooming, resting, and host feeding, exce pt host feeding on A. theophrasti was not observed. Implications of th is study for silverleaf whitefly management through conservation and a ugmentation of native flora and fauna are discussed.