Demography and Randomized Life Table Statistics for Peach Twig Borer <I>Anarsia lineatella</I> (Lepidoptera: Gelechiidae)

Abstract

This work studies for first time the effect of constant temperatures (15, 20, 25, 30 and 3 degrees C) on the demography of Anarsia lineatella Zeller (Lepidoptera: Gelechiidae) based on jackknife and bootstrap randomization methods. Male and female longevity was substantially reduced at the higher temperatures in contrast to intermediate and lower temperatures. According to a second order polynomial regression function, high correlations were observed between temperatures and the age of first reproduction as well as temperature and oviposition times. Net reproductive rate was highest at 25 degrees C and 74.172, while the intrinsic rate of increase displayed its highest values at 30 degrees C and was estimated to be 0.238. Birth rate and finite capacity of increase were higher at 30 degrees C and estimated to be 0.235 and 1.268, respectively. Mean generation time and doubling time varied significantly with temperature and the shortest mean generation and doubling time was obtained at 30 degrees C (25.566 and 2.909 d respectively). Life expectancy had its lowest value 10.3 d at 25 degrees C, whereas cohorts that were maintained at 20 and 15 degrees C increased their life expectation approximately three to sixfold.

Do Insect Populations Die at Constant Rates as They Become Older? Contrasting Demographic Failure Kinetics with Respect to Temperature According to the Weibull Model

“…In summary, all field sampling procedures did not involve endangered or protected species and no specific permissions were needed for these actions. The settlement was kept in constant laboratory conditions at 25°C, 65±5% RH and 16:8 h L: D as described in previous works [ 17 , 23 ]. Five age-synchronized cohorts consisting of 30–50 experimental individuals for each status were established with newly emerged adults and were watched over time.…”

“…Single-sex populations used for survival studies consisted of males and females in approximately equal ratios. Experimental populations were maintained under controlled conditions at five constant temperature regimes, 15, 20, 25, 30 and 35° C, with constant light cycles (16:8 h L:D) and a relative humidity of 65% [ 17 , 23 ]. To avoid any irreducible variation in life spans that was not associated with the temperature regimes (i.e., quantitative life trait patterns, confounding uncontrolled environmental variations with treatment of genotype effects) the temperature-related life span treatments were performed simultaneously [ 24 ].…”

“…Yet, in contrast to mammals, the aging structures in poikilotherms are intimately associated with environmental conditions [ 15 ]. Temperature in particular possesses a potent influence on insect population dynamics to such a level that the demographic structure of a particular species may display totally different aging trajectories under different conditions [ 16 , 17 ].…”

Mixing times towards demographic equilibrium in insect populations with temperature variable age structures

“…Nevertheless, the choice of appropriate distance measure depends on the research needs and study objectives and the Kullback distance has advantage for the study of population stabilization since it is more sensitive to age patterns of demographic potential as well as closely related to a probability context. Although previous studies have described the detrimental effects of extreme temperatures in insect demography (Damos, 2013), it was almost impossible to forecast the long term effects of these temperatures on population stability because analysis was only based on censored actuarial data and fixed demographic parameters. For example, in most cases extreme temperatures (15°C and 35°C) had the same suppressing effect on basic fitness measures (i.e.…”

“…The species is one of the major economic pests of stone fruits worldwide and much time has been given to its survey observation and control and the biology of the species is described in detail in Damos and SavopoulouSoultani (2009). The population was reared as described by Damos (2013), while actuarial data were registered based on classical works of Keyfitz (1985) and Carey (1993Carey ( , 2001 and as described in prior works by Damos (2013).…”