424 B. B. Fand et al.
1c, and 1d). The first-instar nymphs were highly
sensitive to the temperature extremes; however,
later instars had a better survival at all the tem-
peratures within the evaluated range (Table 1 ).
Longevity of adults (both male and female) de-
creased significantly with increasing tempera-
ture due to increased senescence rates (for both
sexes, df = 3, 2; male: F = 17.47, P = 0.055; fe-
male: F = 12.75, P = 0.074) (Table 1 ; Figs. 2a and
2b). The oviposition showed curvilinear response
with maximum fecundity at 30 °C and dropping
off at temperatures below and above it (second-
order polynomial function, F = 4.16; df = 2, 3;
P = 0.136) (Fig. 3 ). The model predicted favorable
temperature range for P. solenopsis development,
survival, and reproduction between 20 and 35 °C
with maximum population growth potential and
shorter generation length at 30 °C (Fig. 4 ).
Risk Mapping of P. solenopsis
Establishment Risk
Figure 5a indicates regions in India where P. so-
lenopsis population theoretically could establish
according to temperature conditions at current
climate scenario (worldclim data 1950–2000).
Regions with ERI 1 indicate that at least certain
proportion of pest population is always expected
to survive and complete life cycle throughout the
year. The likelihood of permanent establishment
of P. solenopsis is reduced considerably in areas
on a map where ERI is less than one. More than
80 % of area in India, barring extreme Northern
Himalayas and North-Eastern high hills is pre-
dicted with high establishment risk. Besides its
present distribution range, the pest is predictedFig. 1 Temperature-dependent developmental rates (1/day) for immature stages of P. solenopsis: nymph 1 (a), nymph 2
(b), nymph 3 (c), and male pupae (d) (Sharpe and DeMichele model). Bars represent standard deviation of the median