Thorax Width Research Articles

Improving the larvae acceptance rate and morphometric characteristics of queen Apis cerana javana by grafting larvae at different ages

Abstract. Ustadi, Ikhsan N, Junus M, Suyadi. 2021. Improving the larvae acceptance rate and morphometric characteristics of queen Apis cerana javana by grafting larvae at different ages. Biodiversitas 23: 166-170. This study was aimed to evaluate the effect of different ages of grafted larvae on the acceptance rate and morphometric characteristics of queen Apis cerana javana Fabr. The total of 72 larvae were 1, 2, and 3 days old and was reared in 7 colonies with 3 treatments (larvae age) and 6 replications. The morphometrics studied consisted of body length, emergence weight, head length, head width, thorax length, thorax width, fore wing length, fore wing width, abdomen length, and abdomen width. The results showed that the different ages of grafted larvae had a highly significant on body length, emergence weight (P<0.01), significant on abdomen length (P<0.05), but not on head length, head width, thorax length, thorax width, fore wing length, fore wing width, abdomen width, acceptance rate. However, the higher acceptance rate was 73.33% to be found in 1 day old of larvae than in 2 and 3 days old. The age of grafted larvae of 1 day old has a higher body length, emergence weight, and abdomen length (P<0.05) than in 2 and 3 days old of larvae. Thus, it can be concluded that the age of grafted larvae of 1 day old was the best age to queen rearing of Apis cerana javana.

Características de carcaça de caprinos terminados com diferentes níveis de suplementação concentrada e mantidos em caatinga enriquecida com Urochloa trichopus

Abstract The objective of this study was to evaluate the carcass traits of crossbred F1 goats (Boer x non-descript breed) finished on thinned caatinga pasture enriched with signal grass (Urochloa trichopus Stapf.), and receiving supplementation. Twenty-four crossbred F1 goats with 27.00 ± 3.32 kg body weight were used. The supplement was designed to meet the nutritional requirements and animals receiving the highest supplementation level could gain 150g per day. For data analysis, a completely randomized design was adopted, with four treatments (supplementation levels of 0.0%; 0.5%; 1.0% and 1.5% body weight) and six replications (animals). Data were subjected to analysis of variance and regression. Supplementation resulted in an increasing linear effect for slaughter weight, hot carcass weight, cold carcass weight, empty body weight, hot carcass yield and cold carcass yield; and a quadratic effect for biological yield. Weight loss by cooling was not influenced by supplementation. For the results of subjective evaluations, only conformation was influenced by supplementation (P<0.05). For morphometry, a positive linear effect of supplementation was found for thorax perimeter, croup perimeter, croup width, thorax width. The level of supplementation caused a positive linear effect on the weight of most non-edible carcass components, and there was no influence of supplementation on most variables for yield. It can be concluded that increasing levels of supplementation up to 1.5% body weight for F1 goats (Boer x non-descript breed) kept on caatinga pasture results in higher carcass weight and yield.

STUDY ON MORPHOLOGICAL CHARACTERISTIC OF STINGLESS BEE (Heterotrigona itama) IN TERENGGANU

Stingless bee, Heterotrigona itama is one of the most important and effective insect pollinators of many plant species. They can be found in the tropical rain forest where they build their nest in the living trees. This study was conducted to measure the morphological characteristic of H. itama from two different populations which were TKPM (Taman Kekal Pengeluaran Makanan) Kampung Peradong, Manir (A) and Big Bee Honey, Merchang (B), Terengganu. 20 individuals of H. itama adults were taken from each population by using insect net. The external morphologies such as body length, head, abdomen, thorax, leg, tibia, forewing, hindwing and antenna were measured by using DinoLite 2.0. The measurements were recorded and the mean ± standard deviation and range of the measurement data were analysed. Based on Mann-Whitney test, there were significant differences for population B of H. itama in mean of head length (p=0.0016; p<0.05), head width (p=0.0022; p<0.05) and thorax width (p=0.0445; p<0.05). However, there was no difference in body colour for H. itama of both populations. H. itama of population B has a larger segmented body with the range of head length at 1.179 mm to 2.152 mm, head width 1.743 mm to 2.557 mm, and thorax width 1.809 mm to 2.329 mm. For future research, it is suggested that this study can look into the genetic status of this species.

Morphological and behavioural differences facilitate tropical butterfly persistence in variable environments.

The thermal biology of ectotherms largely determines their abundance and distributions. In general, tropical species inhabiting warm and stable thermal environments tend to have low tolerance to cold and variable environments, which may restrict their expansion into temperate climates. However, the distribution of some tropical species does extend into cooler areas such as tropical borders and high elevation tropical mountains. Behavioural and morphological differences may therefore play important roles in facilitating tropical species to cope with cold and variable climates at tropical edges. We used field-validated biophysical models to estimate body temperatures of butterflies across elevational gradients at three sites in southern China and assessed the contribution of behavioural and morphological differences in facilitating their persistence in tropical and temperate climates. We investigated the effects of temperature on the activity of 4,844 individuals of 144 butterfly species along thermal gradients and tested whether species of different climatic affinities-tropical and widespread (distributed in both temperate and tropical regions)-differed in their thermoregulatory strategies (i.e. basking). In addition, we tested whether thermally related morphology or the strength of solar radiation (when butterflies were recorded) was related to such differences. We found that activities of tropical species were restricted (low abundance) at low air temperatures compared to widespread species. Active tropical species were also more likely to bask at cooler body temperatures than widespread species. Heat gain from behavioural thermoregulation was higher for tropical species (when accounting for species abundance), and heat gain correlated with larger thorax widths but not with measured solar radiation. Our results indicate that physiological intolerance to cold temperatures in tropical species may be compensated through behavioural and morphological responses in thermoregulation in variable subtropical environments. Increasing climatic variability with climate change may render tropical species more vulnerable to cold weather extremes compared to widespread species that are more physiologically suited to variable environments.

Possibility to change the body size in worker bees by a combination of small-cell and standard-cell combs in the same nest

The aim of the study was to investigate the impact of the combination of the colony type (kept on small-cell or standard-cell combs) and the width of worker comb cells (small-cell or standard-cell combs) on the body weight and morphometric traits of worker bees. The values of morphometric parameters of worker bees changed within a substantially lower range than the width of their rearing cells. This indicates that the worker body size is relatively constant, and manipulation with the cell width is not a good method for modeling the body size of workers. The reduction in the thorax weight was proportional to the decrease in the comb cell width, and this part of the body proved to be most susceptible to weight reduction caused by the use of small-cell combs. The rearing of workers in small-cell combs in the colony kept on standard-cell combs resulted in an increase in the value of the fill factor (thorax width to cell width ratio). The relatively constant body size of workers in combination with the use of small-cell combs resulting in an increase in the fill factor may be one of the determinants of increased resistance of the insects to Varroa destructor. The values of the morphometric traits commonly used for identification of honeybee subspecies, i.e., the length of the fore wing, the sum of the widths of 3rd and 4thth tergites, and the proboscis length, were inconsiderably altered vs. the changes in the comb cell width, which confirms their high suitability for identification of honeybee subspecies.

Diversification of Sexual Size Dimorphism in Cyclops vicinus

The aim of this study was to qualify the sexual size dimorphism at the both inter and intra-population levels of a copepod species, Cyclops vicinus, populations living in a small-scale geographical range. Sexual size dimorphism is evaluated by the ratio of female to male total length. But, to deep insight into sexual size dimorphism we assumed that the more difference between same measurements on the body from different sexes lead to more sexual dimorphism rate. The samples were taken from four water sources locating east and south-east part of Turkey. The significant inter and intra population differences were detected. The thorax width related measurements (mostly) and abdomen length had the most effective ones with changing order in the different populations on the sexual size dimorphism. Pearson correlation coefficients (r) showed that there were strong positive relationships between sexual dimorphism rate and predator presence (r = 0.88) and water volume of lake (r=0.72), while a moderate negative relationship both with water depth (r= -0.50) and with lake area (r= -0.45).

Prediction of Carcass Traits of Santa Inês Lambs Finished in Tropical Pastures through Biometric Measurements.

Simple SummaryBiometric measurements have been used to estimate the composition and yield of sheep carcass cuts. However, for the most part, they are carried out with animals finished in feedlots and/or with released animals, which do not represent the reality of production systems located in tropical regions because tropical forage grasses are the food base of small and large ruminants and are responsible for most of the meat produced in the tropics. Therefore, the objective was to predict the weights of the primary carcass cuts of Santa Inês lambs finished in tropical pastures through biometric measurements. Adjustments of multiple linear equations and selection of variables to predict carcass characteristics were performed using the STEPWISE option and Mallow’s Cp. The biometric measurements obtained at the time of slaughter can be used as predictive variables of carcass of Santa Inês sheep finished in tropical pastures. The prediction equations are precise and accurate.The aim of this study was to predict carcass traits of Santa Inês lambs finished in tropical pastures by using biometric measurements. Data originated from two experiments involving 56 lambs (32 in experiment I and 24 in experiment II). In both experiments, the sheep were finished in that were finished in pastures of Panicum maximum and Brachiaria brizantha, experiment I being conducted in the rainy season and experiment II in the dry season. The following biometric measurements were recorded before slaughter: body length (BL), withers height (WH), rump height (RH), thorax width (TW), rump width (RW), chest width (CW), heart girth (HG), thigh circumference (TC), rump circumference (RC) and leg length (LL), in addition to live weight at slaughter (SW). After slaughter, hot carcass weight (HCW), cold carcass weight (CCW) and the weights of primal cuts (shoulder, neck, loin, leg and rib) were recorded. In the equations generated to predict SW, HCW and CCW, R2 ranged from 0.58 to 0.91 and the measurements of WH, TC, CW, HG and RW were the most relevant. In the equations developed to predict the weight of primal cuts, in turn, R2 ranged from 0.26 to 0.99. In these models, SW, BL, CW, TC, LL and HG explained most of the variation in the weight of primal cuts. Biometric measurements can be used to accurately and precisely predict HCW, CCW and the weight of primal cuts from the carcass of Santa Inês sheep finished in tropical pastures, since the equations presented R2 and correlation coefficient and agreement above 0.8.

Pesticide Exposure During Development Does Not Affect the Larval Pheromones, Feeding Rates, or Morphology of Adult Honey Bee (Apis mellifera) Queens

Recent work demonstrated that honey bee (Apis mellifera L.) queens reared in pesticide-laden beeswax exhibit significant changes in the composition of the chemicals produced by their mandibular glands including those that comprise queen mandibular pheromone, which is a critical signal used in mating as well as queen tending behavior. For the present study, we hypothesized that pesticide exposure during development would alter other queen-produced chemicals, including brood pheromone in immature queens, thus resulting in differential feeding of queen larvae by nurse workers, ultimately impacting adult queen morphology. We tested these hypotheses by rearing queens in beeswax containing field-relevant concentrations of (1) a combination of tau-fluvalinate and coumaphos, (2) amitraz, or (3) a combination of chlorothalonil and chlorpyrifos. These pesticides are ubiquitous in most commercial beekeeping operations in North America. We observed nurse feeding rates of queen larvae grafted into pesticide-laden beeswax, analyzed the chemical composition of larval queen pheromones and measured morphological markers in adult queens. Neither the nurse feeding rates, nor the chemical profiles of immature queen pheromones, differed significantly between queens reared in pesticide-laden wax compared to queens reared in pesticide-free wax. Moreover, pesticide exposure during development did not cause virgin or mated adult queens to exhibit differences in morphological markers (i.e., body weight, head width, or thorax width). These results were unexpected given our previous research and indicate that future work is needed to fully understand how pesticide exposure during development affects honey bee queen physiology, as well as how various adult queen quality metrics relate to each other.

Phenotypic variation in adults of Chilo partellus (Swinhoe) from diverse ecological regions of India

AbstractGeographic distance and ecological conditions are important factors for phenological differentiation, and the adult morphological characters play significant role in several biological functions in insects. Present study showed significant intraspecific and intersex variation in colour pattern, number of spots and stripes on the forewings of Chilo partellus adults of different ecological populations. Females were comparatively light in colour with less black spots and stripes than the males across populations. Length and width of head, thorax and abdomen, wingspan, and various parts of male and female genitalia varied significantly across C. partellus populations. Abdomen, corpus bursae and papillae anales were significantly longer in females of Hisar as compared to other populations. However, the length of aedeagus was significantly longer in males of Coimbatore and Delhi as compared to other populations. Range of wingspan: body size and body size: genitalia ratios across C. partellus populations were wider in females than males. Wingspan: body size ratio was significantly lower in males of Raichur and females of Hisar and Parbhani as compared to other populations. Body size: genitalia ratio was significantly lower in males of Coimbatore and Hyderabad, and females of Coimbatore, Raichur and Surat as compared to other ecological populations. These findings suggest phenotypic plasticity in C. partellus having implications for phenotypic expression and greater fitness in response to changing climatic conditions.

Appropriate Mesh Size of Insect Screen for the Exclusion of the Cigarette Beetle, Lasioderma serricorne (F.)

Summary Insect screens are often used in tobacco facilities to exclude insect pests. Previous studies using laboratory cultures indicated that screens with openings smaller than 1.0 mm are adequate to prevent the passage of the cigarette beetle, Lasioderma serricorne. The beetles from natural populations are rather heterogeneous, and their body sizes may vary. Studies were conducted to confirm the relationship between mesh sizes and the body sizes of the cigarette beetles that can pass through the screens and to elucidate the size distribution of wild beetles. The results revealed that meshes can protect against beetles whose thorax width is larger than the openings in the mesh. Additionally, the widths of the prothoraxes of wild beetles captured in pheromone traps, which were generally considered to be male, ranged from 727–1070 μm (N = 169), and approximately 90% of the beetles had thoraxes that were narrower than 1000 μm. These data led to the conclusion that a 1.0 mm opening mesh is insufficient to protect against the cigarette beetle. Thus, Tyler standard #24 mesh (= US standard #25 mesh: 0.71 mm opening/sieve size) is recommended as an insect screen for tobacco facilities.

The Effects of Co-Enzyme Q10 and Caffeine on Morphometric Characteristics of Queen Honey Bees

Honey bee queen quality is a critical factor of colony performance. Indications of such qualities can manifest themselves through morphological traits such as wet weight and thorax width. Improving such characteristics is driven in part by nutritional provision in queen-cell-builder hives. We investigated the potential to improve queen quality by adding coenzyme Q10 (endogenous antioxidant) and caffeine (central nervous system stimulator) to feeder syrup in queen-cell-builder colonies for 15 and 20 days prior to grafting, two sets of queens were reared. We recorded subsequent wet weight, body length, head width and length, thorax and wing width and length, and spermathecae diameter. The queen-cell acceptance rate was not affected by either treatment or graft period. Coenzyme Q10 increased wet weight, body and wing length in the first graft, and thorax width, wing length and spermathecae diameter in the second graft. The caffeine treatment increased head and thorax length in first graft and thorax width in the second. A mix of the two substances (coenzyme Q10 and caffeine) increased head width in the first graft and spermathecae diameter in the second graft. This study suggests that the application of coenzyme Q10 to cell-builder colonies at least 15 days prior to grafting can increase reared wet weight (the most significant quality indicator) and thorax width of queen bees.

Laboratory Growth of <i>Anopheles gambiae</i> (Diptera: Culicidae) and Morphological Determinism of Moulting

Growth in arthropods in general and in insects in particular, is supposed to be discontinuous and occurs during moulting. In Culicidae in general and Anopheles in particular, the number of moults is five with the fourth which gives the pupae. It is known that moulting in insects is a genetic and physiological phenomenon. Most physiological reactions are triggered by chemical or physical stimuli. The pressure exerted by the growth of the larval body on the exocuticle is one of the triggers of moulting. The objective of this work was therefore to determine the exact timing of the first three moults that determine the growth of An. gambiae larvae from egg hatch to pupation to highlight the role of increased larval size in the stimulation of moulting. We therefore, undertook to rear larvae of this anopheline species in the laboratory under conditions close to their natural environment from hatching to pupation. The length and width of the head, thorax and abdomen were recorded daily. Data analysis showed that the size of the head and thorax remained constant for the first three days (D0 to D2) of development and abdomen’s length for the first two days and then increased daily until day seven (D7) when it stopped. These observations led us to say that the M1 moult occurs at end of the third day of development and the M3 moult at end of the eighth day; the M2 moult could not be determined. All these observations led to the conclusion that the larval growth of An. gambiae has a continuous regimen and the growth of the head and thorax of the larva plays a crucial role in the onset of moulting.

Screening Newly Developed Bermudagrasses for Host Plant Resistance against Fall Armyworm (Lepidoptera: Noctuidae)

The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is an important pest of warm-season turfgrass species, including bermudagrass (Cynodon spp.). Bermudagrass is a popular turfgrass that is widely planted on golf courses, athletic grounds, and ornamental landscapes across the country and throughout the world. Spodoptera frugiperda infestation is often sporadic; however, when it does occur, damage can be severe. Host plant resistance against S. frugiperda can be a valuable tool for reducing or preventing the use of insecticides. Therefore, the objective of this study was to determine resistance against S. frugiperda in a few promising bermudagrasses. Fourteen experimental bermudagrass genotypes plus two control cultivars, ‘Zeon’ zoysiagrass (resistant control) and ‘TifTuf’ bermudagrass (susceptible control), were evaluated against S. frugiperda to determine host plant resistance in the laboratory. The results showed that the resistant control, ‘Zeon’ zoysiagrass, was more resistant than the other genotypes to S. frugiperda larvae. To determine the response of the experimental lines to S. frugiperda as compared with that of the controls, three indices were developed based on survival, development, and overall susceptibility. According to the susceptibility index, ‘13-T-1032’, ‘T-822’, ‘11-T-510’, ‘12-T-192’, ‘11-T-56’, ‘09-T-31’, ‘11-T-483’, and ‘13-T-1067’ were the top-ranked bermudagrasses. Among these, the responses of ‘13-T-1032’, ‘T-822’, ‘11-T-510’, ‘11-T-56’, ‘09-T-31’, and ‘11-T-483’ were comparable to that of ‘TifTuf’, and antibiosis was the underlying mechanism of resistance. Additionally, larval length, head capsule width, and weight were negatively associated with the days of pupation and adult emergence and positively associated with pupal length, thorax width, and weight. These results will help refine future breeding and with investigations of resistance against the fall armyworm.

Radiographic Reference Intervals of the Cardiac Silhouette Width in the Bald Eagle (Haliaeetus leucocephalus).

Radiograph imaging is an important diagnostic tool for assessing cardiac size in avian patients. The bald eagle (Haliaeetus leucocephalis), once on the United States Federal List of Endangered and Threatened Wildlife and Plants, is now a thriving species in the United States. However, there is surprisingly little information regarding bald eagle cardiac reference values obtained through radiographic imaging for use in assessment of cardiac disease in this species. This study was performed to establish reference values of cardiac size in the bald eagle. Ventrodorsal radiographic images were taken from 9 healthy birds obtained from a raptor rehabilitation facility. Cardiac silhouette width to thorax width, cardiac silhouette width to sternum width, cardiac silhouette width to hepatic silhouette width, and cardiac silhouette width to coracoid width were obtained. Ratios were calculated between the respective areas measured. The results showed that the cardiac silhouette averages 44%-52% of the thoracic width, 71%-86% of the sternal width, 94%-117% of the width of the hepatic silhouette, and 500%-920% of the coracoid width. In the individuals studied there was a strong correlation between cardiac silhouette width to thoracic and sternal width whereas cardiac width with hepatic and coracoid widths had a moderate to weak correlation respectively. The values obtained in this study can be used to radiographically assess the cardiac size of bald eagles, thus aiding in the diagnosis of cardiomegaly in this species.

Visuo-motor biases in buff-tailed bumblebees (Bombus terrestris)

ABSTRACT Bees provide a good model to investigate the evolution of lateralization. So far, most studies focused on olfactory learning and memories in tethered bees. This study investigated possible behavioural biases in free-flying buff-tailed bumblebees (Bombus terrestris) by analysing their turning decisions in a T-maze. Bees of various size were trained to associate a syrup reward with a blue target placed at the centre of the T-maze. The bees were then tested over 16 trials by presenting them with blue targets at the end of the maze’s arms. The maze was rotated 180° after the first 8 trials to control for environmental factors. The number of turnings to the left and right arms were analysed. The bees sampled exhibited a population-level rightward turning bias. As bumblebees vary significantly in size with large bees being better learners than smaller ones, we measured the thorax width to identify a possible relationship between size and bias. No significant correlation was identified. This study shows that bees present lateralization in a visuo-motor task that mimics their foraging behaviour, indicating a possible specialization of the right side of the nervous system in routine tasks.

Multivariate analysis of body morphometric traits in conjunction with performance of reproduction and milk traits in crossbred progeny of Murrah × Jafarabadi buffalo (Bubalus bubalis) in North-Eastern Brazil.

We studied the relationship between body morphometric traits, and their underlying association with milk production (MP), lactation length (LL), first calving interval (FCI) and subsequent calving interval (CI) of crossbred progeny of Murrah × Jafarabadi buffalo aiming to assist in selection programs. We carried out principal component analysis (PCA) of the body morphometric traits, which include breast width (BW), thigh width (THW), hip width (HW), rump width (RW), rump length (RL), body depth (BD), body length (BL), height withers (HEW), rear height (RH), shoulder width (SW), thorax width (TW), loin width (LW), distance from the head to ischium (DHI), and thoracic perimeter (TP). We determined the association of morphometric traits with milk/reproduction traits using canonical correlation analysis (CCA). The analysis revealed that the first six PCA accounted for 82.14% of the total observed variation, and the traits THW, HW, TW, LW, RW, HEW, TP, RH, and BW, accounted for almost half (48.00%) of the total variance indicating a higher contribution in body structural conformation. The first canonical function was significant (p<0.05), accounted for 72.46% of the total variance, and the canonical correlation was 0.56, indicating the dependence between both groups of traits. Higher canonical loadings were obtained for LL (0.49), FCI (0.46), BW (-0.71), BL (-0.56), DHI (-0.34), HEW, (-0.38) and TP (-0.50). These traits were most important for the derivation of canonical statistical variables, and presented a higher canonical correlations (r) between the dependent (LL/FCI) and independent (BW, BL, DHI, HEW and TP) groups. The results could suggest that the body morphometric traits THW, HW, TW, LW, RW, HEW, BD, TP, RH, and BW could play important role in body structural composition, indicating a suitable functional type, and aid designing of selection programs for buffalo breeding.

Estimating body weight, body condition score, and type traits in dairy cows using three dimensional cameras and manual body measurements

This study aimed to determine body weight (BW), body condition score (BCS), and dairy type traits (DTT) of Holstein heifers and lactating cows using three-dimensional (3D) cameras, in addition to evaluating the sensitivity of this system over time and the best sensor position. Twenty-eight cows and twenty-seven heifers were used. Measurements of BW and BCS were taken over five months, and one single measurement was taken for each of the 23 lactating cows that had the official Holstein register to evaluate DTT. Images were taken using a Microsoft Kinect 3D camera from lateral and dorsal perspectives to predict BW and BCS, synced with MATLAB software. Fourteen and thirteen measurements were taken from dorsal and lateral perspectives, respectively. Then, the SAS GLMSELECT LASSO procedure was used to test the linear and quadratic effects, and the ratios of the obtained variables. Subsequently, selected characteristics were tested using PROC MIXED of SAS to fit the models and predict BW and BCS. In addition, DTT were evaluated using 3D camera images to estimate the Holstein Association official grade. The udder, chest, and close back side were used to complement the lateral and dorsal images. Biometric measurements and 3D camera data were also compared to each other using a paired t-test. The obtained models to predict BW had an R2 of 0.89 and 0.96 and RMSE of 49.20 and 26.89 for lateral and dorsal perspectives, respectively. The lateral model was composed of body weight, height, body depth, and body lateral volume. The dorsal model was composed of rump width, thorax width, and dorsal area. The model obtained to predict BCS had an R2 of 0.63 and 0.61 and RMSE of 0.16 and 0.17 for lateral and dorsal images respectively. The lateral model was composed of body depth, lateral area, and body weight divided by height. The dorsal model was composed of dorsal length, dorsal area, dorsal volume, and body weight to dorsal area ratio. Among all official 15 evaluated DTT, 4 were adequately predicted (P < 0.05) by 3D cameras. Ten DTT were adequately predicted (P < 0.05) by biometric measurements. In conclusion, 3D cameras have a good prospective future commercial use and either lateral or dorsal images could be used for BW prediction however the BCS models still need improvements. The udder traits were those DTT with the best prospective use, due to the highest accuracy.

A Small Parasitoid of Fire Ants, Pseudacteon obtusitus (Diptera: Phoridae): Native Range Ecology and Laboratory Rearing

The high diversity within a guild of Pseudacteon Coquillet (Diptera: Phoridae) parasitoid flies hosted by the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), may be based on several niche axes, including host size specialization, host location cues, climatic responses, and tolerances. The recently described species, Pseudacteon obtusitus Plowes, Folgarait, and Gilbert (Diptera: Phoridae), is one of the smallest species in this group (with a thorax width of only 0.3 mm), and appears to locate ant hosts on foraging trails as well as at nest disturbances. Here we examine the ecology, phenology, and development of this parasitoid at sites in Corrientes, Argentina. Pseudacteon obtusitus has 2 seasons of peak abundance, and exhibits low tolerance for cold temperatures or extended cold periods. It preys on the smallest ant workers (typically 0.6 mm head width) independent of the ant size offered, and has a male biased sex ratio (mean 2.78:1). Developmental times ranged from 35 d at 27 °C to 44 d at 22 °C. This species holds interest for inclusion among the multi-species assemblage of parasitoid flies considered for biological control of S. invicta in its invasive range in North America.

Not all cicadas increase thermal tolerance in response to a temperature gradient in metropolitan Seoul

Rapid anthropogenic alterations caused by urbanization are increasing temperatures in urban cores, a phenomenon known as the urban heat island (UHI) effect. Two cicada species, Cryptotympana atrata and Hyalessa fuscata (Hemiptera: Cicadidae), are abundant in metropolitan Seoul where their population densities correlate strongly with UHI intensities. Such a positive correlation between cicada density and UHI intensity may be possible if cicada abundance is linked to a certain thermal tolerance. We tested this hypothesis by investigating variation in morphology and thermal responses of two cicada species along a thermal gradient in Seoul and surrounding areas. The morphological responses were measured by metrics such as length, thorax width and depth, and mass. The thermal responses were measured in terms of minimum flight temperature, maximum voluntary temperature and heat torpor temperature. First, we observed a species-specific variation in thermal responses, in which C. atrata displayed a higher thermal threshold for maximum voluntary and heat torpor temperatures than H. fuscata. Second, a positive association between temperature conditions and body sizes were displayed in females H. fuscata, but not in either conspecific males or C. atrata individuals. Third, C. atrata exhibited similar thermal responses regardless of habitat temperature, while H. fuscata in warmer areas showed an increase in heat tolerance. In addition, H. fuscata individuals with bigger thorax sizes were more heat-tolerant than those with smaller thoraxes. Overall, our research is the first to detect a variation in thermal responses and body size of H. fuscata individuals at a local scale. More investigations would be needed to better understand the adaptation mechanisms of insects linked to UHI effects.

Morphological changes associated with brachypterous Triatoma guasayana (Hemiptera, Reduviidae) and their relationship with flight

Flight is the main form of dispersion for adult triatomines. It is postulated here that some body morphological parameters vary in T. guasayana according to a greater or lesser wing development, which would allow to estimate their flight capacity. Furthermore, there are observations which allow to suggest that the wings alone would not present the entirety of the information on the flight ability of an insects. It is postulated here that some body morphological parameters vary in T.guasayana according to a greater or lesser wing development. The study aims to verify the hypothesis that the variation of the wing phenotype in triatomines is accompanied by variations of other body structures, particularly the head. Geometric morphometry of heads, thorax width and wing length of T.guasayana brachypterous and macropterous was used. The results allow to confirm that there is a relationship between the wing condition of T. guasayana and other variables – unrelated to wings – that can be associated with flight capacity. The shape of the head changes with the wing condition. The results obtained suggest that the diversity of wing morphotypes imply a diversity in head conformation, suitable for flight: macropterous have a greater distance between eyes and shorter heads, while brachy or micropterous exhibit smaller eyes and larger heads. For the first time, brachypterous individuals of T.guasayana are recorded here, posing the existence of a pronounced alary polymorphism in this species. Identifying these markers in triatomines is of special importance to understand the processes of domicile recolonization after vector control campaigns.