الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Ecological factors affecting the developmental performance and reproductive fitness 1.1. Effect of nutritious food type 1.1.1. Effect of food quality of conspecific eggs (cannibalism) on the developmental and reproductive performances of C. maculata Egg cannibalism serves various functions in the Coccinellidae. Here we examined the fitness consequences of egg cannibalism by neonates, fourth instar larvae, and prereproductive adults of Coleomegilla maculata DeGeer, with beetles fed a diet of Ephestia kuehniella Zeller eggs. Cannibalism of two eggs by neonates had no effect on development, and cannibalism of five eggs by fourth instars did not benefit any aspect of reproduction, but delayed pupation slightly. Cannibalism of eggs by prereproductive adults had no effect on reproductive success in any combination of reciprocal crosses of cannibals and non-cannibals. Females did not recognize, nor avoid consuming, their own clutches, and cannibalism propensity did not change following mating and onset of oviposition in either sex. These results contrast with those for more strictly aphidophagous species in which larvae gain developmental benefits, and females may recognize and avoid filial egg clusters while using cannibalism to interfere with conspecific females, whereas males reduce egg cannibalism after mating because they cannot recognize filial clusters. Egg cannibalism may confer developmental benefits to C. maculata when diet is suboptimal, as previously shown, but no such benefits were evident on the high-quality E. kuehniella egg diet. Female C. maculata do not require aphids to reproduce and distribute their eggs broadly in the environment, given that larvae can develop on pollen and non-aphid prey. Thus, C. maculata is not subject to the intraspecific competition that selects for cannibalism in more aphidophagous species, and lacks many secondary adaptations associated with the behaviour. 1.1.2. Effect of food quantity of moth eggs on body size of H. axyridis Body size is a trait with many potential impacts on fitness. Adult body size can affect the strength of condition-dependent parental effects that determine offspring phenotypes, with potentially important transgenerational consequences. We used larval food deprivation (four hours daily access) to create a cohort of Harmonia axyridis Pallas (Coleoptera: Coccinellidae) that weighed 60% of controls reared on ad libitum food (eggs of Ephestia kuehniella Zeller). Small pairs had lower 20-day fecundities and reduced egg fertility relative to large pairs. Both egg incubation periods and pupation times were shortest when both parents were small, and longest when both parents were large, with reciprocal crosses intermediate. There were no consistent effects of parental body size on larval development time, but progeny of small females mated to large males were delayed relative to other treatments. Progeny of large pairs had the heaviest adult weights at emergence, and those of small pairs, the lightest, with progeny of reciprocal crosses intermediate. Small females produced the lightest female offspring, whereas small males sired the lightest male offspring, suggesting stronger responses to epigenetic signals from parents of the same sex. These results indicate that H. axyridis cohorts maturing with abundant food will produce progeny with larger potential body size and fitness, whereas those experiencing food limitation will confer size and fitness limitations to the subsequent generation, with potentially important implications for short-term population dynamics. 2.Physiological factors affecting the developmental performance and reproductive fitness 4.2.1.a. Fitness costs of flight activity on C. maculata and H. convergens The flight activity of Coleomegilla maculata DeGeer and Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae) was examined by observing tethered beetles in the laboratory. C. maculata were fed eggs of Ephestia kuehniella Zeller, as were larval H. convergens, whereas adult H. convergens were fed Melanaphis sacchari (Zehntner) to induce egg maturation; adults of both species received water and diluted honey. A spot of magnetic paint was applied to one elytrum of each beetle, which then adhered to a small neodymium magnet attached to a thread. Beetles were permitted 1 h flight opportunities daily for 3-d periods, first as virgins on their fifth day of adult life, secondly after mating, thirdly after females began oviposition, and fourthly after prey were withheld and egg maturation and oviposition ceased. Both species exhibited low flight activity as virgins, and whereas C. maculata females increased their activity after mating, H. convergens females did not. Flight activity in C. maculata did not change with onset of oviposition, whereas it increased in H. convergens males, but not females. In contrast, H. convergens females increased their flight activity after cessation of oviposition, whereas C. maculata females did not. Female flight activity when either virgin or mated correlated weakly with fecundity in C. maculata, but not in H. convergens. Species differences are discussed in the context of nutritional ecology; H. convergens usually enters diapause immediately following emergence, and is more dependent on aphids for reproduction, whereas C. maculata develops and reproduces on a wider range of foods and is not so constrained. 2.2. Fitness costs of limb regeneration 2.2.1. Limb regeneration in the Asian ladybeetles H. axyridis: 2.2.1.1. Direct costs of limb regeneration in the Asian ladybeetles H. axyridis: Previous work revealed that Harmonia axyridis Pallas (Coleoptera: Coccinellidae) in Beijing, China, could regenerate a forelimb amputated in the fourth instar; 75% of surviving individuals fully regenerated the limb during pupation. In this study, we tested a population of H. axyridis invasive in North America and found that virtually 100% of beetles surviving the operation successfully regenerated the limb. Ablated/regenerated beetles spent longer in pupation, and emerging females were smaller than controls. However, reproductive success was unaffected in all pairwise crosses of control/regenerated adults; there were no differences in pre-oviposition period, the time required to produce 10 clutches, 10-day fecundity, or the fertility of eggs, whereas ablated/regenerated parents paid a developmental cost, their progeny obtained benefits. Offspring of crosses that included a regenerated parent tended to have faster larval development than the control cross, although not all were significantly different from controls. However, when either or both parents were ablated and regenerated, their daughters were heavier than controls at emergence. Limb regeneration during pupation appears to activate a physiological cascade which increases the magnitude of beneficial parental effects normally conferred to progeny, possibly via pleiotropic effects. The invasive North American H. axyridis population appears to have higher regeneration capacity than the Chinese population tested previously, although how regeneration capacity might be associated with invasiveness remains unclear. Limb regeneration ability may be a side effect of selection on other traits that confer high fitness under either natural or sexual selection, as it seems unlikely to confer fitness benefits directly in this species. 2.2.1.2. Limb regeneration in the two Nearctic ladybeetles: The ability of Coleomegilla maculata DeGeer and Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae) to regenerate, during pupation, a foreleg, that was amputated early in the fourth instar were examined. Leg regeneration was somewhat better in H. axyridis (100% complete regeneration), than in H. convergens and C. maculata (80.7% complete, 12.5% partial, and 6.8% failed) and (72.2%, 20.5% and 7.2%) respectively. The life history costs of ablation/regeneration were slight, with pupation delayed by a day or less and a slight decrease in fresh body mass of H. axyridis females but with fresh mass at emergence in the other both species, pupation time and reproductive performance unaffected in all species. A number of progeny were reared from the second clutch of each female in four reciprocal crosses between regenerated and control (unoperated) beetles. Offspring of crosses that included a regenerated parent in H. axyridis tended to have faster larval development than the control cross, although not all were significantly different from controls. However, when either or both parents were ablated and regenerated, their daughters were heavier than controls at emergence. In H. convergens, mating treatment affected eclosion time, whereas in C. maculata, eclosion time, larval development, and pupation time were all affected. Experiment-wide larval mortality was higher in H. convergens than in C. maculata, but lower when both H. convergens parents regenerated. Parental mating treatment did not affect adult weight in either species, but development of C. maculata progeny was faster when only the sire regenerated, and slower when the only the dame regenerated, whereas progeny of regenerated sires completed pupated faster than those sired by controls. Limb regeneration ability may be a side effect of selection on other traits that confer high fitness under either natural or sexual selection, as it seems unlikely to confer fitness benefits directly in these species. We infer that genes activated during regeneration have pleiotropic effects with subtle, gender-specific, epigenetic consequences. If these pleiotropic effects are genetically linked to important traits, regenerative genetic elements could be conserved in coccinellids via natural selection acting on these traits rather than on regenerative ability per se. 2.3. Fitness costs of reflex bleeding on development and reproduction of C. septempunctata and H. variegata Fourth instar duration of C. septempunctata and H. variegate which surviving bleed treatments were not significantly different from those of control in both species. Plus, the pupation time in C. septempunctata was not significantly different from control in case of H. variegate. Moreover, males and females of control group were significantly heavier than those of bled treatments in H. variegate. In case of C. septempunctata non bled males were significantly heavier than those of bled treatments but females were not. On the other hand, results obtained showed no significant effects of treatment on the pre-oviposition period of females in either species nor on their fecundity and fertility. Also, the present study there were significant effects of mating treatment on the time required for eclosion of C. septempunctata eggs but H. variegata did not. Similarly, the duration of larval development was significantly impacted across treatments in C. septempunctata and the fastest development occurred when both parents were subjected to bled three time and again that was not the case for H. variegata. In addition, C. septempunctata progeny obtained from stressed parent to bleed kept gaining benefits over their counterparts from H. variegata in pupation time. Which The former’s progeny spend significantly shorter periods in pupation than those of non-bled treatment. Moreover, treatments had significant impact on male and female fresh body weight in C. septempunctata offspring and H. variegata had not. There were no significant effects of treatment on the pre-oviposition period of females in either species nor on their fecundity nor, on egg fertility.
Results of developmental progeny revealed that the time required for eggs to hatch was affected by mating treatment in C. septempunctata with earlier eclosion occurring when the parent stressed to bleed, whereas eclosion of H. variegata eggs were not significantly affected by treatment. The duration of larval development was significantly impacted across treatments in C. septempunctata and the fastest development occurred when both parents were subjected to bled three time early during their fourth instar and the slowest larval development occurred in control treatment (non-bled). But in H. variegata control/bled treatments had no significant effect. Although parental mating treatment did not affect pupation time in H. variegata, it did in C. septempunctata, pupation was faster when both parents faced one bled event. Adult fresh weight at emergence was affected by treatment in both C. septempunctata males and females, while it was unaffected by treatment in H. variegata males and females.