Br. Krasnov et al., Development rates of two Xenopsylla flea species in relation to air temperature and humidity, MED VET ENT, 15(3), 2001, pp. 249-258
The rate of development of immature fleas, Xenopsylla conformis Wagner and
Xenopsylla ramesis Rothschild (Siphonaptera: Xenopsyllidae) was studied in
the laboratory at 25 degreesC and 28 degreesC with 40, 55, 75 and 92% relat
ive humidity (RH). These fleas are separately associated with the host jird
Meriones crassus Sundevall in different microhabitats of the Ramon erosion
cirque, Negev Highlands, Israel. This study of basic climatic factors in r
elation to flea bionomics provides the basis for ecological investigations
to interpret reasons for paratopic local distributions of these two species
of congeneric fleas on the same host. Both air temperature and RH were pos
itively correlated with duration of egg and larval stages in both species.
Change of humidity between egg and larval environments did not affect durat
ion of larval development at any temperature. At each temperature and RH, t
he eggs and larvae of X. ramesis did not differ between males and females i
n the duration of their development, whereas female eggs and larvae of X. c
onformis usually developed significantly faster than those of males. For bo
th species, male pupae developed slower than female pupae at the same air t
emperature and RH. Air temperature, but not RH, affected the duration of pu
pal development. At each humidity, duration of the pupal stage was signific
antly longer at 25 degreesC than at 28 degreesC: 15.3 +/- 1.7 vs. 11.7 +/-
1.2 days in X. conformis; 14.1 +/- 2.0 vs. 11.5 +/- 1.7 days in X. ramesis,
with a significantly shorter pupal period of the latter species at 25 degr
eesC. These limited interspecific bionomic contrasts in relation to basic c
limatic factors appear insufficient to explain the differential habitat dis
tributions of X. conformis and X. ramesis.