Electronic recording of lifetime locomotory activity patterns of adult medflies.

Age-specific and diurnal patterns of locomotory activity, can be considered as biomarkers of aging in model organisms and vary across the lifetime of individuals. Τhe Mediterranean fruit fly (medfly), Ceratitis capitata, is a commonly used model-species in studies regarding demography and aging. In the present study, we introduce a modification of the automated locomotory activity electronic device LAM25system (Locomotory Activity Monitor)-Trikinetics, commonly used in short time studies, to record the daily locomotory activity patterns of adult medflies throughout the life. Additionally, fecundity rates and survival of adult medflies were recorded. Male and female medflies were kept in the system tubes and had access to an agar-based gel diet, which provided water and nutrients. The locomotory activity was recorded at every minute by three monitors in the electronic device. The locomotory activity of females was higher than that of males across the different ages. For both sexes locomotory rates were high during the first 20 days of the adult life and decreased in older ages. The activity of males was high in the morning and late afternoon hours, while that of females was constantly high throughout the photophase. Negligible locomotory activity was recorded for both sexes during the nighttime. Males outlived females. Fecundity of females was higher in younger ages. Our results support the adoption of LAM25system in studies addressing aging of insects using medfly as a model organism

Effects of early-life protein starvation on longevity and sexual performance of male medfly.

Using a well-established model species for demographic, behavioural and aging research, the Mediterranean fruit fly (Ceratitis capitata), we explored whether nutritional stress early in adult life affects the sexual performance and survival in older ages. To do so we established two different protein starvation (PS) protocols that included the elimination of proteinaceous diet either before or after sexual maturity of male medflies. The frequency of sexual signalling and the age of death were daily recorded. Sexual signalling is directly related with male mating success in this model system. PS early in adult life results in high mortality rates (similar to sugar-only fed males), which are gradually restored in more advanced ages. Provision of a proteinaceous diet following early-life PS increases straightaway male sexual signalling to levels similar with those having continuous access to proteinaceous diet. Switching diet regimes from a protein-free to a protein-rich one progressively compensates mortality rates. Apparently, males prioritize sexual signalling over lifespan. PS after attaining sexual maturity significantly reduces both longevity and sexual performance. Access to protein only early in life is insufficient to support lifetime energy-consuming behaviours such as sexual signalling. Continuous access to a proteinaceous diet determines both lifetime sexual performance and longevity. Early in life PS males prioritize the allocation of nutritional elements, when available, in sexual activities over soma-maintenance

Adaptation of an Invasive Pest to Novel Environments: Life History Traits of Drosophila suzukii in Coastal and Mainland Areas of Greece during Overwintering

Drosophila suzukii is a polyphagous pest of small and soft fruit, originating from Asia, which has spread and established in Europe and the USA. Adults exhibit seasonal phenotypes, i.e., summer morphs (SM) and winter morphs (WM) to cope with fluctuating environmental conditions. WM have a darker cuticle and larger wings compared to SM, while WM females experience reproductive dormancy. We studied the life history traits (lifespan, female reproductive status and number of produced offspring) of WM and SM that were exposed to winter field conditions of a coastal and a mainland agricultural area, with mild and cold winter climates, respectively. Mated adults of each phenotype were individually placed in vials bearing nutritional/oviposition substrate, and transferred to the field from November 2019 to May 2020, when the death of the last individual was recorded. Almost all SM females (90%) and no WM female carried mature ovarioles before being transferred to the field. WM exhibited a longer lifespan than SM adjusting for location and sex. Differences in survival between the two phenotypes were more pronounced for adults kept in the mainland area. The majority of SM females produced offspring during overwintering in the mild coastal area, but only a few SM were reproductively active in the cold mainland area. Some WM females produced progeny during overwintering in the mild conditions of the coastal area, but all WM females were in reproductive arrest in the mainland area. Overwintering females in the coastal area had a shorter lifespan and produced more progeny than those kept in the mainland area. High survival rates of WM provide indications of the successful performance of this phenotype in the adverse conditions of the cold climates. Additionally, the continuous reproductive activity of SM females and the onset of progeny production by WM females during overwintering in the coastal area indicate that the insect remains reproductively active throughout the year in areas with mild climatic conditions. Our findings support the successful adaptation of D. suzukii in both areas tested and can be used for the development of area-specific population models, based on the prevailing climatic conditions

Description of Rhagoletis cerasi (Diptera: Tephritidae) Pupal Developmental Stages: Indications of Prolonged Diapause

The European cherry fruit fly, Rhagoletis cerasi (L.) (Diptera: Tephritidae), is the key pest of sweet and sour cherries in many European countries and west Asia. It is a univoltine species of the west Palaearctic zone that undergoes obligatory pupal diapause. In this study, the development of R. cerasi pupae that were brought to an optimum temperature for postdiapause development following a long chilling period is described. The six most representative developmental stages within the puparium are illustrated, and the developmental progression among the stages after the end of the chilling period is quantified. Within 20 d postchilling, there was a gradual progress from stage I to pharate adult. However, similar to 30% of the pupae remained at the transitional stage II, after 20 d at 25 degrees C (optimum temperature for development). This suggests that a proportion of pupae remain at an intermediate developmental stage for an extended period of time that goes beyond 20 d postchilling. The pupal stage II might be related to diapause termination and responsiveness to environmental cues. It may also define the time before developmental progress to pharate adult. This finding agrees with previous studies proposing that a number of R. cerasi pupae undergo prolonged diapause, though the morphological characteristics of these pupae have never been described before

Remaining life expectancy (expected number of days remaining at day x) for females fed either a full or a protein-deprived diet that mated or remained unmated at day 15 or 40.

<p>Sample sizes of each age class are given in parenthesis.</p

Smoothed mortality rates with 95% confidence intervals of females fed a full diet that mated (continuous line) or remained unmated (dotted line) at t = 15 (A) and t = 40 (B) days.

<p>Smoothed mortality rates with 95% confidence intervals of females fed a full diet that mated (continuous line) or remained unmated (dotted line) at t = 15 (A) and t = 40 (B) days.</p

Copulation success of females fed a full (left) and a protein-deprived (right) diet, at a young (15 days) and an old (40 days) age.

<p>The percentage of the females that had initiated egg production one day before the mating test is given in parenthesis. Asterisks (*) indicate significant differences (<i>P</i><0.05).</p

Smoothed proportion of fecundity rates (age specific fecundity of treatment/age specific fecundity of control) with 95% confidence intervals of females fed a protein-deprived diet that mated (continuous line) or remained unmated (dotted line) at t = 15 (A) and t = 40 (B) days old.

<p>Smoothed proportion of fecundity rates (age specific fecundity of treatment/age specific fecundity of control) with 95% confidence intervals of females fed a protein-deprived diet that mated (continuous line) or remained unmated (dotted line) at t = 15 (A) and t = 40 (B) days old.</p

Smoothed proportion of fecundity rates (age specific fecundity of treatment/age specific fecundity of control) with 95% confidence intervals of females fed a full diet that mated (continuous line) or remained unmated (dotted line) at t = 15 (A) and t = 40 (B) days.

<p>Smoothed proportion of fecundity rates (age specific fecundity of treatment/age specific fecundity of control) with 95% confidence intervals of females fed a full diet that mated (continuous line) or remained unmated (dotted line) at t = 15 (A) and t = 40 (B) days.</p