Adult holometabolous insects may derive metabolic resources from either larval or adult feeding, but little is known of whether adult diets can compensate for deficiencies in the larval diet in terms of stress resistance. We investigated how stress resistance is affected and compensated for by diet across life stages in the marula fruit fly Ceratitis cosyra (Diptera: Tephritidae). Larvae were fed diets containing either 8% torula yeast, the standard diet used to rear this species, or 1% yeast (low protein content similar to known host fruit). At emergence, adults from each larval diet were tested for initial mass, water content, body composition, and desiccation and starvation resistance or they were allocated to one of two adult diet treatments: sucrose only, or sucrose and yeast hydrolysate. The same assays were then repeated after 10 days of adult feeding. Development on a low protein larval diet led to lower body mass and improved desiccation and starvation resistance in newly emerged adults, even though adults from the high protein larval diet had the highest water content. Adult feeding decreased desiccation or starvation resistance, regardless of the diet provided. Irrespective of larval diet history, newly emerged, unfed adults had significantly higher dehydration tolerance than those that were fed. Lipid reserves played a role in starvation resistance. There was no evidence for metabolic water from stored nutrients extending desiccation resistance. Our findings show the possibility of a nutrient-poor larval environment leading to correlated improvement in adult performance, at least in the short term. RESULTS Choice of larval dietsNo pupae were obtained from the 0% torula yeast larval diet (Table 1). There was a significant difference between the number of pupae obtained from the remaining three larval diets (F 3,16 =265.42, P< 0.0001). The number of pupae from the 4% and 8% torula yeast larval diets was significantly higher than from the 1% torula yeast diet. Larval diet also had a significant effect on adult emergence 4

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In the family Miridae (Hemiptera), females and males attract each other by means of sex pheromones. Among insects, these pheromones are characterized by a variety of chemical structures, including saturated and unsaturated, long- and short-chain esters, as well as unsaturated ketoaldehydes. The aim of this study was to assess the chemical emissions in Eccritotarsus catarinensis (Carvalho) and Eccritotarsus eichhorniae Henry to determine their similarity and their possible role in reproductive isolation mechanisms that led to speciation. Chemicals emitted by adults inserted in air-entrainment chambers were collected in absorbent tubes and were analyzed using gas chromatography–mass spectrometry (GC-MS). Results from the GC-MS library indicate that E. catarinensis females and E. eichhorniae males have chemical emissions that their conspecific and the same sex of the other species lack. Also, E. catarinensis males lack benzenebutanoic that the other sexes have, while E. eichhorniae males have 1,2,3,4-tetrahydro-6-(phenyl methyl) that other sexes lack. Further analysis using statistical approaches (e.g., cluster analysis, multidimensional scaling plot, and principal component ordination) indicated that cross-breeding pairs have similar chemical emissions in that E. eichhorniae females had similar chemical emissions to those of E. catarinensis males, while E. catarinensis females had similar chemical emissions to those of E. eichhorniae males. These unique differences in chemical emissions could be caused by the recently identified differences in the metathoracic scent glands and the antennae of the two Eccritotarsus species, and they may serve as a basis in explaining the interbreeding and mating incompatibilities reported in these two Eccritotarsus species.

Many biological control agents have been released to manage the water hyacinth, Pontederia (Eichhornia) crassipes (C. Martius) Solms-Laubach (Pontederiaceae). They include two Eccritotarsus sources from Brazil and Peru. Distinguishing features between the two were found, necessitating their redescription. The Brazil source remained Eccritotarsus catarinensis (Carvalho), whereas the Peru source is Eccritotarsus eichhorniae Henry. Our objectives in this laboratory study were to assess the mate choice in the two species and, thus, determine which species performs better than the other. Mate choice in the form of no-choice, bichoice, and multichoice tests were conducted within and between species in a 3:1, 2:1, and 1:1 sex ratios. The E. catarinensis pair had short copula latency but long copula duration in multichoice experiments, whereas the E. eichhorniae pair had short copula latency but long copula duration in no-choice experiments. In no-choice and bichoice experiments, E. eichhorniae♀ and E. eichhorniae♂ outcompeted E. catarinensis♀ and E. catarinensis♂. In multichoice experiments, E. catarinensis♂ outcompeted E. eichhorniae♂, whereas E. eichhorniae♀ outcompeted E. catarinensis♀. Despite being shown to be more fecund, E. eichhorniae is likely not to outcompete E. catarinensis where the two species co-occur and that E. catarinensis♂ and E. eichhorniae♀ will outcompete their counterparts. Previous research indicated that when E. catarinensis♂ and E. eichhorniae♀ are crossed, they produce few offspring, underscoring the need to confirm if the two species will coexist, compete, or displace each other in their natural habitats. Our findings further support that prezygotic reproductive isolation mechanisms led to the speciation of these species.