No abstract

No abstract

No abstract

Body contents of the black-legged tick, Ixodes scapularis, and brown dog (or kennel) tick, Rhipicephalus sanguineus, were screened by fungal culturing for more virulent strains to use in biological control and to investigate the propensity of ticks as endosymbiotic hosts. A low incidence of internal fungi was observed in both ticks, averaging < 20% recovery. Noteworthy in R. sanguineus was identification of Scopulariopsis carbonaria Morton and Smith (previously unknown within ticks) among the few internal isolates as well as the common internal associate S. brevicaulis (Sacc.) Bainier. Ixodes scaputaris ticks were similarly devoid of fungi except for recovery ofMetarhizium anisopliae (Metsch.) that is likely present as a parasite. Compositions of external mycoflora were alike (13 Deuteromycetes and three Zygomycetes) and reflect fungi prevalent in soil, leaf litter and organic debris. Despite this rich external mycoflora, internal fungi appear to be restricted to Scopulariopsis spp. and harboring this fungus is linked to the large wax glands ('sagittiform sensilla') that are characteristic of metastriate, but not prostriate (Ixodes), ticks. However, low levels of fungi within R. sanguineus indicate that the prevalence of tick-borne fungi is not as widespread as previously thought. The fact that not all classified entomopathogenic fungi recovered from tick surfaces were found inside the tick suggests that successful parasitism may be limited to a few select fungi (e.g., Metarhizium spp.) in nature, thus affecting potential biological control applications.

2006) Structure and function of the urnulae in Balaustium sp. (Parasitengona: erythraeidae) featuring secretion of a defensive allomone and alarm pheromoneABSTRACT -In studying predator-avoidance tactics of adult Balaustium sp. mites, a characteristic red fluid was observed leaking from a single pair of tubercles (umulae) that project from the dorsal idiosoma, just behind the eyes. Until now, the urnulae had no known function, but served a useful taxonomic purpose. When threatened, mites were observed actively secreting umulae-derived fluid that was spread over their body surface by means of numerous setae. Subsequent application of the fluid to mealworm beetle larvae (Tenebrio molitor) resulted in sudden diminished ant attacks, suggesting that this secretion serves a defensive role as an allomone. True to semiochemical parsimony, this secretion also prompted an excited dispersal response among conspecific mites, indicating that it also functions as an alarm pheromone, perhaps as an injury cue. More pronounced predator defense and alarm activities are displayed by mite body fluids, indicating that the activity of the emission from the umulae parallels that ofhemolymph. Based on positive staining with ammoniacal silver nitrate, their capacity to secrete, and additional morphological and histological investigations carried out, the role of the urnulae is clearly glandular. Of interest is that the defensive mechanism appears to operate by a novel form of reflex bleeding reminiscent of aposematic beetles.