In vivo and in vitro rearing of Pediculus humanus capitis (Anoplura: Pediculidae).

Four geographically distinct colonies of the human head louse, Pediculus humanus capitis De Geer (Anoplura: Pediculidae) were reared on a live host and exhibited significantly different life history patterns. Florida head lice exhibited approximately 10% slower development and approximately 15% reduced longevity relative to California or Ecuador head lice. Fecundity (4.9 +/- 0.2 eggs/female/d) and fertility (76.4 +/- 2.9% mean hatching rate) declined over the lifetime of female lice, especially when separated from males (i.e., unmated recently). All four colonies (above plus one from Panama) were similar in their ability to tolerate starvation, although older stages tended to die sooner. An in vitro feeding apparatus was developed to rear head lice. Teneral first instar lice were placed on human hair tufts on the upper side of membrane-covered feeders, which were immersed bottom-side down within a vessel containing warmed human blood. Relative to lice reared on a human host, in vitro-reared lice required a significantly longer time (10-20%) to molt and survived a significantly shorter time as adults (30-50%); the addition of antibiotics did not adversely affect louse development. Teneral first instars were more likely than any other stage to feed through the membrane. Lice spent a significantly greater proportion of time searching in the in vitro apparatus than on a host, but the proportion of time spent feeding did not differ. This research is the first to demonstrate that head lice can be reared successfully in vitro through a complete life cycle.

An automated feeding apparatus for in vitro maintenance of the human head louse, Pediculus capitis (Anoplura: Pediculidae).

An automated feeding apparatus was developed to maintain the human head louse (Pediculus capitis DeGeer) in vitro. With the use of valves and timers, banked human blood and saline from refrigerated reservoirs were pumped into and flushed out of the system every 7 d. During this rotational interval, bloodmeals were provided to head lice continuously and ad libitum through a stretched Nescofilm-silicone sandwich membrane. Compared with our previous in vitro human head louse-rearing apparatus, greater numbers of lice could be fed simultaneously with minimal human monitoring. Development of second to third instars and third instars to adults was significantly faster when lice were reared in vivo than on either of the in vitro rearing systems; there was no significant difference in the duration of the first instar. Although fecundity and hatch rates were significantly higher for female lice reared in vivo, similar trends have been observed for other membrane-fed arthropods. Body lice (Pediculus humanus L.) and bed bugs (Cimex lectularius [L.]) also completed most of their life cycle on this apparatus. Our automated mass-rearing system has broad applications for maintaining fluid-sucking ectoparasites and will facilitate various toxicological, behavioral, and disease-transmission investigations.

Predatory behaviors of Neoseiulus californicus and Galendromus helveolus (Acari: Phytoseiidae) attacking Oligonychus perseae (Acari: Tetranychidae).

Predatory behaviors of Neosieulus californicus (McGregor) and Galendromus helveolus (Chant) attacking Oligonychus perseae Tuttle, Baker and Abbatiello on avocado leaves were videotaped and analyzed. Behaviors were recorded for "fresh" predators that were used < or = 48 hr post receipt from a commercial insectary and "cold stored" predators that were maintained at 12 degrees C for approximately 14 days. Fresh and cold stored G. helveolus were observed to attack O. perseae only after invading webbed nests. Conversely. fresh and cold stored N. californicus employed three different modes of predatory attack: (1) intercepting and attacking migrant O. perseae outside of web nests: (2) attacking prey through nest webbing; or (3) invading and attacking O. perseae inside nests. Predatory efficacy of both N. californicus and G. helveolus was reduced following cold storage. as both species engaged in certain predatory behaviors less frequently in comparison to predators that were not stored at low temperatures. Our observed results for N. californicus and G. helveolus attacking O. perseae are interpreted in relation to the chaetotaxy hypothesis, which proposes that phytoseiid invasion efficiency and propensity of webbed nests is facilitated by dorsal setal lengths.

Movement of Rhodnius prolixus (Hemiptera: Reduviidae) within a simulated house environment.

We observed the movement, attraction, and resting behavior of laboratory Rhodnius prolixus Stål within a house environment, simulated by a Styrofoam box. Movement of R. prolixus into various refuge types (fiberpots or white-, cream-, or black-colored modified Gomez-Nunez boxes) at different strata was assessed. Greater numbers of fifth instars sought a refuge than third instars. Fasted nymphs sought a refuge more than fed nymphs. Our simulated house environment showed potential as a laboratory arena to observe the resting preferences, dispersal, and response of kissing bugs to potential attractants. Our data indicated that fiberpot refuges may serve as an effective and inexpensive monitoring device to detect low density kissing bug infestations.