Number Of Ovarioles Research Articles

Comparative study of the reproductive activity of Calliptamus barbarus (Costa, 1839) and Calliptamus wattenwylianus (Pantel, 1836) in a subhumid bioclimatic region

The reproductive activity of Calliptamus barbarus and Calliptamus wattenwylianus was investigated to understand population dynamics and reproductive potential in a subhumid bioclimatic zone. Specimens were collected from July to October and dissected to assess ovarian development and egg-laying activity. The number of ovarioles, determined at birth, ranged from 62 to 67 for C. wattenwylianus and 48 to 58 for C. barbarus. Higher fertility was observed in C. wattenwylianus, with egg production increasing during the first oviposition for both species. The average reproductive yield was notable for C. barbarus (85.99%) and C. wattenwylianus (86.56%). Oocyte resorption occurred mainly during drought (August-September) and cold periods (October-November). C. wattenwylianus females reached maturity earlier, beginning in August, compared to C. barbarus. Egg production began in July for C. wattenwylianus and in September for C. barbarus. Oocyte retention rates were 5% for C. barbarus and 9% for C. wattenwylianus. These findings provide insights into reproductive patterns in North African Orthoptera, with implications for pest control in subhumid regions.

Role of nuclear protein Akirin in the modulation of female reproduction in Nilaparvata lugens (Hemiptera: Delphacidae).

Introduction: Akirin as a highly conserved transcription factor, exerts a profound influence on the growth, development, immune response, and reproductive processes in animals. The brown planthopper (BPH), Nilaparvata lugens, a major pest in rice production in Asia, possesses high reproductive capacity, a critical factor contributing to reduced rice yields. The aims of this study were to demonstrate the regulatory role of Akirin in the reproduction of BPH. Methods: In this study, quantitative PCR (qPCR) was used to detect the mRNA expression of genes. RNA interference (RNAi) was used to downregulate the expression of Akirin gene, and RNA sequencing (RNA-seq) was used to screen for differentially expressed genes caused by Akirin downregulation. Hormone contents were measured with the enzyme linked immunosorbent assay (ELISA), and protein content was evaluated with the bicinchoninic acid (BCA) method. Results: Using BPH genome data, we screened for an Akirin gene (NlAkirin). An analysis of tissue-specific expressions showed that NlAkirin was expressed in all tissues tested in female BPH, but its expression level was highest in the ovary. After inhibiting the mRNA expression of NlAkirin in BPH females, the number of eggs laid, hatching rate, and number of ovarioles decreased. Transcriptome sequencing was performed, following a NlAkirin double-stranded RNA treatment. Compared with the genes of the control, which was injected with GFP double-stranded RNA, there were 438 upregulated genes and 1012 downregulated genes; the expression of vitellogenin (Vg) and vitellogenin receptor (VgR) genes as well as the mRNA expression of genes related to the target of rapamycin (TOR), juvenile hormone (JH), and insulin pathways involved in Vg synthesis was significantly downregulated. As a result of NlAkirin knockdown, the titers of JH III and Ecdysone (Ecd) were downregulated in unmated females but returned to normal levels in mated females. The ovarian protein contents in both unmated and mated females were downregulated. Discussion and conclusion: Our results suggest that NlAkirin affects female BPH reproduction by regulating the mRNA expression of genes related to the Vg, VgR, TOR, JH, and insulin signaling pathways, in addition to the titers of JH III and Ecd. The findings of this research provide novel insights into the regulatory role of Akirin in insect reproductive capacity.

Gene Protein Sequence Evolution Can Predict the Rapid Divergence of Ovariole Numbers in the Drosophila melanogaster Subgroup.

Ovaries play key roles in fitness and evolution: they are essential female reproductive structures that develop and house the eggs in sexually reproducing animals. In Drosophila, the mature ovary contains multiple tubular egg-producing structures known as ovarioles. Ovarioles arise from somatic cellular structures in the larval ovary called terminal filaments (TFs), formed by TF cells and subsequently enclosed by sheath (SH) cells. As in many other insects, ovariole number per female varies extensively in Drosophila. At present, however, there is a striking gap of information on genetic mechanisms and evolutionary forces that shape the well-documented rapid interspecies divergence of ovariole numbers. To address this gap, here we studied genes associated with Drosophila melanogaster ovariole number or functions based on recent experimental and transcriptional datasets from larval ovaries, including TFs and SH cells, and assessed their rates and patterns of molecular evolution in five closely related species of the melanogaster subgroup that exhibit species-specific differences in ovariole numbers. From comprehensive analyses of protein sequence evolution (dN/dS), branch-site positive selection, expression specificity (tau), and phylogenetic regressions (phylogenetic generalized least squares), we report evidence of 42 genes that showed signs of playing roles in the genetic basis of interspecies evolutionary change of Drosophila ovariole number. These included the signaling genes upd2 and Ilp5 and extracellular matrix genes vkg and Col4a1, whose dN/dS predicted ovariole numbers among species. Together, we propose a model whereby a set of ovariole-involved gene proteins have an enhanced evolvability, including adaptive evolution, facilitating rapid shifts in ovariole number among Drosophila species.

Occurrence of giant migratory locust Locusta migratoria (Acrididae) on Tsushima Island, Japan

This study focused on the populations of Locusta migratoria (Linnaeus, 1758) on Tsushima Island, Japan, which exhibited the largest mean adult body size when compared to other populations from various climatic regions. Certain individuals, designated as “giant locusts,” displayed exceptionally large sizes, with females and males identified when with head widths surpassing 10.5 mm and 8.0 mm, respectively. The maximum weight recorded for a giant locust was 8.9 g, in contrast to other examined females with the maximum weight ranging from 3.1 to 5.5 g. Notably, giant females exhibited the ability to yield larger egg pods and progeny compared to their counterparts. A positive correlation emerged between body size of adult females and the number of ovarioles. To explore the potential heritability of body size, selection experiments were conducted across two generations. A significant impact of selection on adult body size was apparent at LD 12:12h, whereas this effect was not evident at LD 16:8h. Furthermore, crossing experiments showed that body size at hatching closely resembled that of the female parent or demonstrated dimensions intermediary between the two parents, suggesting a complex genetic basis for the observed body size variations. This study provides no evidence of genetic differentiation between the giant locusts and the other locusts on this island.

The oviposition preference and offspring performance of Aethina tumida (Coleoptera: Nitidulidae).

Given the rapid spread and potential harm caused by the small hive beetle, Aethina tumida (Coleoptera: Nitidulidae) in China, it has become imperative to comprehend the developmental biology of this invasive species. Currently, there is limited knowledge regarding the impact of A. tumida female oviposition site preference on larval growth and development. To examine this, we investigated the ovipositional preference of adult female A. tumida on bee pupae, beebread, banana, and honey through a free choice test. Furthermore, we assessed the impact of these food resources on offspring performance, which included larval development time, survival, wandering larvae weight, emerged adult body mass, reproduction, and juvenile hormone titer. Our results showed that A. tumida females exhibited a strong preference for ovipositing on bee pupae compared to other diets, while showing reluctance toward honey. Moreover, A. tumida larvae that were fed on bee pupae displayed accelerated growth compared to those fed on other diets. Furthermore, A. tumida fed on bee pupae exhibited higher weights for wandering larvae, and emerged adult, increased pupation rates, enhanced fecundity and fertility, as well as a larger number of unilateral ovarioles during the larval stage when compared to those fed on other diets. Overall, the results indicate that the oviposition preferences of A. tumida females are adaptive, as their choices can enhance the fitness of their offspring. This finding aligns broadly with the hypothesis of oviposition preference and larval performance. This study can provide a foundation for the development of attractants aimed at promoting the oviposition of the A. tumida adults.

Increased Mass-Rearing of Queens in High Royal-Jelly-Producing Honey Bee Colonies (Apis mellifera ligustica) Generates Smaller Queens with Comparable Fecundity

The mass rearing of high-quality queen bees is an essential beekeeping practice for producing new queens to maintain colony productivity. A strain of high royal-jelly-producing bees (RJBs; Apis mellifera ligustica) in China exhibits high potential for the rapid mass rearing of queens. To explore the potential changes in the quality of mass-reared queens, a set of morphometric traits and the sealed brood area were compared between the queens reared from 64 and 320 queen cells in RJB colonies. The increase in the queen cell number was found to induce a slightly but significantly reduced body weight and smaller wing length and thorax width in the reared queens at emergence. However, the ovariole number and sealed brood area, an indicator of the queen fecundity, were not observed to be significantly influenced. With respect to body weight and ovariole number, all the reared queens satisfied the current criteria for high-quality queens. Our findings provide evidence for the efficient mass production of high-quality queens using RJB colonies.

Effect of Spermidine Supplementation on Testicular And Ovarian Development in Sex-limited and Non-sex-limited Bivoltine Silk Worm Breeds of <i>Bombyx mori</i> L

Silk worm Bombyx mori L is a holometabolous, lepidopteran model for investigating the effect of various molecules. The sex-limited character of cocoon color is useful for the separation of male and female pupae during commercial seed production. Fecundity is the major limitation of cocoon colour sex-limited breeds. Spermidine is a polyamine, present in all living cells involved in the growth and reproduction of many organisms. The effect of spermidine on testicular and ovarian development in the selected bivoltine sex-limited breed; APS27SL and non-sex-limited hybrid; APS45 x APS12 is studied in the present work. Results showed that foliar feeding of spermidine significantly increased pupal growth, testicular and ovarian growth, number of ovarioles and ovules in the sex-limited breed. Moreover, increased expression of Bm-tektin was observed in the testes of spermidine fed groups. Thus, the study suggests that foliar feeding of spermidine can be used to overcome the limitation of reproductive potential in sex-limited breeds.

Developmental plasticity of thermal performance curve for reproduction in Drosophila melanogaster.

In ectotherms, body temperature is a crucial determinant of performance and fitness, as captured by thermal performance curves (TPCs). Since survival in variable environments is often facilitated by phenotypic plasticity, to reliably assess an organism's ability to cope with thermal changes, it is necessary to characterize not only TPCs but also their reaction norms. While previous studies have investigated plasticity in TPCs, these studies focus only on selected parameters and a few developmental temperatures. They may, therefore, overlook the complexity of developmental plasticity in TPCs. Here, we examined the full extent of thermal developmental plasticity in TPCs for fecundity and hatchability in Drosophila melanogaster. By employing a factorial design with ten developmental and twelve adult temperatures, our study enabled a comprehensive characterization of reaction norms of all key TPC parameters. We found that developmental temperature had a significant impact on the egg production rate, with minor effects on other TPC parameters. Nonoptimal developmental temperatures negatively affected most TPC parameters, whereas development at 22-26 °C maximized reproductive fitness. We also revealed that developmental plasticity for the maximum reproductive performance might be predominantly caused by developmentally-induced changes in ovariole number. Our results in conjunction with previous studies on intraspecific variation suggest that any changes in TPC for reproduction primarily involve the egg production rate, indicating that adaptive evolution and phenotypic plasticity followed the same pathway. Overall, our findings underscore the limitations of developmental plasticity in enhancing reproductive fitness, suggesting that while certain traits, such as egg production rate, may be relatively plastic, these changes may not be sufficient to enable effective adjustment to environmental shifts.

Effect of two larval diets on the reproductive parameters of the housefly, Musca domestica L. (Diptera, Muscidae)

Abstract Deep understanding of the optimal reproductive and biological parameters is necessary to obtain the maximum egg production in captive rearing of Musca domestica, the common housefly. The effect of larval diet is explored in this study, using two different media: poultry manure and an artificial medium based on cereals mixed with meat. The preimaginal mortality and development time, with other reproductive parameters that indirectly affect adult fecundity as: ovary and wing size, fluctuating asymmetry, and cuticular hydrocarbon composition, were analysed. The results show that poultry manure was related with better efficacy values, lower larval mortality rate, and a sex-dependent effect in fecundity. Asymmetry fluctuation and different hydrocarbon composition was detected in females. The females from larvae that grew on manure presented bigger ovaries and oocytes, but a smaller number of ovarioles per ovary. Their morphological asymmetry was also lower; and the cuticular hydrocarbon composition was distinct from the rest of the adults, with more alkanes and less alkenes than males or females related with the artificial diet. As conclusion, the effect of larval substrate on the survival and fecundity parameters is evident. The implications for the mass production of the house fly as animal feed are also indicated.

Leaf extracts of three native medicinal plants, damages the reproductive organs of the filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae)

The limitations encountered with chemical insecticides to control mosquito borne diseases and proliferation of mosquitoes, has prompted the researchers to focus on developing insecticides of botanical origin. Acetone and methanol extracts of three medicinal plants were tested against the first instar of Culex quinquefasciatus and the lethal concentrations estimated. The column fractions of methanol extracts of the selected plants, Andrographis paniculata, Polyalthia longifolia and Bougainvillea spectabilis exhibited significant larvicidal activities. The 24 hr LC50 of the methanol-ethyl acetate (MeOH-EA) 4:1column fractions of A. paniculata and P. longifolia and nHexane-ethyl acetate (nH:EA) 5:5 fraction of B. spectabilis are 3.013, 145.67 and 221.38 ppm, respectively. The effective concentration which affects 50% emergence (EC50) of the treated larvae is 1.05 ppm, 72.6 ppm and 110.693 ppm respectively for the active column fractions. Total developmental duration and growth index were also affected by the column fractions. Exposure of the sub lethal dose affect the gonotrophic cycle of Cx. quinquefasciatus and also exhibited more than 90% control of reproduction in the tested group of treated males with untreated females (T♂ x UT♀) and exhibited higher sterility index. Dissection of the ovary and testes of Cx. quinquefasciatus after treatment with column fractions shows that the testicular development was drastically affected. The testes and ovaries of the treated mosquitoes showed variation in length and size and number of ovarioles when compared to control mosquitoes. The tested botanicals at comparatively lower dosages could effectively interfere with reproductive viability and check proliferation in next generation.

Rearing Host Dependency of Ovariole Number and Body Size in Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae)

Campoletis chlorideae has great biocontrol potential against some major noctuid pests. In order to achieve the commercial development and utilization of C. chlorideae, this study focused on the effect of rearing host species and larval instars on the ovariole number and body size of this wasp. Firstly, the morphology of the reproductive system and ovarioles of female wasps were observed. The number of ovarioles displayed great variability and asymmetry between bilateral ovaries. Moreover, the effect of four host species on ovariole number and body size of C. chlorideae were studied. The wasps had a larger ovariole number and body size when reared in Helicoverpa armigera. Additionally, the ovariole number and body size were larger when reared in the third instar larvae than in the first or second instar larvae of H. armigera. There was a strong positive correlation between the ovariole number and body size of C. chlorideae. The ovariole number and body size of the wasp could be improved under optimized artificial rearing conditions. According to these results, body size combined with ovariole number can be used as an important index to evaluate the quality of C. chlorideae. This study provides important clues for the development and application of biocontrol using C. chlorideae.

Honey bee maternal effects improve worker performance and reproductive ability in offspring.

Maternal effects are an evolutionary strategy used to improve offspring quality. In an example of maternal effects in honey bees (Apis mellifera), mother queens produce larger eggs in queen cells than in worker cells in order to breed better daughter queens. In our current study, morphological indexes, reproductive tissues, and the egg-laying ability of newly reared queens reared with eggs laid in queen cells (QE), eggs laid in worker cells (WE), and 2-day-old larvae in worker cells (2L) were evaluated. In addition, morphological indexes of offspring queens and working performance of offspring workers were examined. The thorax weight, number of ovarioles, egg length, and number of laid eggs and capped broods of QE were significantly higher than those of WE and 2L, indicating that the reproductive capacity of QE group was better than that of other groups. Furthermore, offspring queens from QE had larger thorax weights and sizes than those from the other two groups. Offspring worker bees from QE also had larger body sizes and greater pollen-collecting and royal jelly-producing abilities than those of other two groups. These results demonstrate that honey bees display profound maternal effects on queen quality that can be transmitted across generations. These findings provide a basis for improving queen quality, with implications in apicultural and agricultural production.

The relationship between the internal and external morphological parameters of honeybee queens (Hymenoptera: Apidae) and the determination of morphological variation

This study was carried out to determine the crucial external and internal morphological characteristics for evaluating queens in three rearing periods (May, June, and July). Data of 65 queens reared from the local honeybees of the Sanliurfa (Apis mellifera L.) and Anatolian (Apis mellifera anatoliaca) honeybee colonies were used. Discriminant and principal component analyses (PCA) were done for thirty-one external and internal morphological characteristics of queens. The highest weight of the queen at emergence was determined in May for the Sanliurfa queens and in June for the Anatolian queens. The averages in ovary weight and spermathecae diameter of queens were found to be non-significant according to groups and periods. The number of ovarioles of the queens was different according to rearing period. Using the left basitarsus width variable, the Sanliurfa and Anatolian queens were classified correctly to their pre-assigned groups using discriminant analysis (73.8%). According to the result of PCA applied to all variables of queens, nine components explained 81.68% of the total variation. The seven variables in the first principal component were the left basitarsus length, the right hindleg length, the left hindleg length, the right basitarsus length, the left tibial length, the right tibial length, and the left basitarsus width. The forewing and the hindwing characteristics were included in the second principal component, and the number of ovarioles was included in the third principal component. The study shows that genotypes can be discriminated using the hindleg variables, in particular, as well as the internal and external morphological parameters of the queens.

Same-sex Pairs Retain Their Reproductive Capacity as a Potential Opportunity for Individual Reproductive Success in Termites

In eusocial termites, successful pairing is an essential element of dispersal and distribution after the departure of alates from natal colonies. Two situations could arise during the pairing process: mixed-sex pairs and same-sex pairs. However, most previous studies focused on mixed-sex pairs, overlooking groups formed by same-sex pairings, especially potential fecundity (the total number of oocytes or ovarioles), oogenesis and the development stage of oocytes of females in female-female pairs, and spermatogenesis and testis development of males in male-male pairs. In this study, through experimentation, we investigated the reproductive ability of virgin dealates based on various pairing types as mentioned above. We found that the life spans of virgin dealates can cover 1 yr or even more when they establish a nest with a partner, which is more than 10-fold longer than the life span of individuals establishing a colony alone. After 1 yr of pairing, the potential fecundity of virgin same sex dealates did not degenerate significantly compared with newly emerged dealates, including the number of ovarioles, size of testis, oogenesis, and the development stage of the oocytes. Moreover, when individuals of same-sex pairings experimentally changed into mixed-sex pairs after 1 yr, the eggs produced in the colony hatched into larvae. These findings suggest that dealates which through same-sex pairs retain fecundity after 1 yr have more reproductive potential than dealates that failed to pair with heterosexuals, shedding light on the ecological significance of homosexual behaviors in terms of the successful extension and fecundity of eusocial termites.

A synopsis of the numbers of testicular follicles and ovarioles in true bugs (Heteroptera, Hemiptera) - sixty-five years of progress after J. Pendergrast's review.

The structure of testes and ovaries can be described in its simplest form by the number of follicles and ovarioles they contain. Sixty-five years after the last review of the internal reproductive systems in true bugs (Heteroptera), the data accumulated today on the number of testicular follicles and ovarioles in their gonads are summarized. In addition, data on the number and type (mesadenia/ectadenia) of accessory glands are given. The hemipteran suborder Heteroptera constitutes one of the most diverse groups of non-homometabolous ('Hemimetabola') insects, comprising more than 40,000 described species worldwide and approximately 100 families, classified into seven infraorders. Data are available for all infraorders; however, more than 90% of studied species belong to the largest and most evolutionarily derived infraorders Cimicomorpha and Pentatomomorpha. In true bugs, in general, the number of follicles varies from one to nine (in a testis), and the number of ovarioles varies from two to 24 (in an ovary). Seven follicles per testis and seven ovarioles per ovary prevail being found in approximately 43.5% (307 species) and 24.4% (367 species) of studied species, respectively. Such a structure of testes and ovaries is considered an ancestral character state in the Heteroptera. In the evolution of this group, the number of follicles and ovarioles both increased and decreased, but the trend towards a decrease clearly prevailed.

Comparative reproductive biology of pre-, imaginal, and neotenic castes of the Asian termite Coptotermes gestroi (Blattaria, Isoptera, Rhinotermitidae).

The Asian subterranean termite Coptotermes gestroi is a worldwide structural pest, although its reproductive biology has been poorly investigated due to a cryptic habit and occurrence of polycalic nests. In this study, we investigated ovarian development and oogenesis in different-aged females of C. gestroi: fourth-instar nymphs, non-functional neotenics, alates, and functional queens. We show that the ovaries develop gradually according to their age and functionality, as younger individuals possess immature oocytes, whereas alates and functional queens always undergo vitellogenesis. Oocytes were classified into previtellogenic (stages I, II, and III) or vitellogenic (stages IV, V, and VI). Ovary development varied among non-functional neotenics, and a rapid differentiation and/or the presence of primary reproductives are believed to influence such a maturation. Immature oocyte stages were shared between fourth-instar nymphs and neotenics. These characteristics, together with other neotenic features (wing buds, body pigmentation, and eye color), should be evaluated in detail aiming to clarify which nymphal instars differentiate into secondary reproductives. Oogenesis was not uniform among alate females, and cross-sectional area of terminal oocytes was significantly smaller in alates when compared to functional queens, suggesting different degrees of maturation in swarming individuals. Functional queens always had mature terminal oocytes (stage VI). Ovariole number and oocyte maturation in C. gestroi relies on several factors and may therefore differ among individuals of the same caste. Future studies should take into account these reproductive features to evaluate how they impact colony development.

Four Insulin-Like Peptides Orchestrate Reproductive Signaling of the Green Lacewing, Chrysopa pallens (Rambur) (Neuroptera: Chrysopidae)

Abstract In insects, insulin signaling plays a pivotal role in the regulation of growth, metabolism, reproduction, and aging. Revealing the regulatory roles of insulin signaling in natural enemy insects is helpful for developing artificial approaches to promote reproduction. In this study, the expression of four insulin-like peptides (ILPs) in female adults of the natural predator Chrysopa pallens was analyzed by quantitative real-time-polymerase chain reaction (qRT-PCR) and their functions were investigated by RNA interference (RNAi). C. pallens ILP1 (CpILP1) and C. pallens ILP4 (CpILP4) showed a gradual increase in mRNA levels from early adult stages to later stages. However, C. pallens ILP2 (CpILP2) and C. pallens ILP3 (CpILP3) had an opposite expression curve with a high transcript level at the beginning of the adult stage and a gradual reduction thereafter. All four CpILPs showed high expression levels in the ovary, but CpILP2 transcripts were also abundant in fat bodies. Disruption of CpILP1 and CpILP2 expression by RNAi-mediated knockdown strikingly suppressed ovarian development and reduced C. pallens vitellogenin gene 1 (CpVg1) transcripts. Depletion of CpILP3 transcripts did not significantly decrease ovariole number but drastically reduced CpVg1 expression. Interference with the expression of CpILP4 significantly inhibited ovarian development but did not suppress CpVg1 expression. All gene knockdowns failed to dramatically impair total fecundity and egg quality. These data suggest that the four C. pallens ILPs are involved in reproductive signaling at different degrees.

The impact of the Hsp67Bc gene product on Drosophila melanogaster longevity, fecundity, and acute heat stress tolerance.

Drosophila melanogaster Hsp67Bc is a heat- and cold-inducible small heat shock protein that participates in the prevention of aggregation of misfolded proteins and in macroautophagy regulation. Overexpression of the Hsp67Bc gene has been shown to enhance macroautophagy in Drosophila S2 cells, and the deletion of this gene leads to the formation of a slightly increased number of autophagic vacuoles in the fruit f ly brain neurons. Recently, we found that Hsp67Bc-null D. melanogaster f lies have poor tolerance to cold stress (0 °C) of various durations. In the present work, we investigated how the Hsp67Bc gene deletion affects the f itness of fruit f lies under normal conditions and their tolerance to elevated temperatures at different developmental stages. Larvae and pupae were not adversely affected by the Hsp67Bc gene deletion, and adult Hsp67Bc-null f lies showed an extended lifespan in comparison with the control at normal (24–25 °C) and elevated temperature (29 °C), and after acute heat stress (37 °C, 2 h). At the same time, the fecundity of the mutant females was lower by 6–13 % in all tested environments, except for permanent maintenance at 29 °C, where the mean numbers of eggs laid by the mutant and control f lies were equal. We explain this phenomenon by a reduced number of ovarioles in Hsp67Bc-null females and enhanced macroautophagy in their germaria, which promotes the death of forming egg chambers. In addition, short heat stress (37 °C, 2 h), which increased the control line’s longevity (an effect common for a wide range of organisms), had a negative impact on the lifespan of Hsp67Bc-null f lies. Therefore, Hsp67Bc-null D. melanogaster have an extended lifespan under normal and elevated temperature conditions, and reduced fecundity and thermal stress tolerance.

Improving Egyptian Honeybee Characteristics by Crossing with Carniolan Drones Using Instrumental Insemination

Apis mellifera the Western honeybee, is a widespread species that has differentiated into numerous geographical strains or subspecies. These subspecies differ in various characteristics, such as morphology, behavior, and ecology. In the present investigation, different morphometric characteristics of the Carniolan ( ) and Egyptian ( ) subspecies were Apis mellifera carnica Apis mellifera lamarckii compared with their hybrids and backcrosses. The rates of increase in some morphometric characteristics as evidence of hybridization between an Egyptian virgin queen and Carniolan drones being 1.7, 3.2, 0.15, 0.5. 2.4, 0.33 and 1.43 percent for forewing length, width, ovariole number, spermatheca diameter, third tergit length, width, and fourth tergit length. Moreover, the backcross generation showed reductions for all queen characteristics resulting from hybridization between an Egyptian virgin queen and Carniolan drones being 2.35, 4.058.6, 3.1, 0.93,4.2, 1.04, 0.34,and 11.5% for forewing width, ovariole number, spermatheca diameter, third tergit length, third tergit width, fourth tergit length, fourth tergit width and for queen weight.

Improving Egyptian Honeybee Characteristics by Crossing with Carniolan Drones Using Instrumental Insemination

Apis mellifera strains or the Western honeybee, is a widespread species that has differentiated into numerous geographical subspecies. These subspecies differ in various characteristics, such as morphology, behavior, and ecology. In the present investigation, different morphometric characteristics of the Carniolan (Apis mellifera carnica) and Egyptian (Apis mellifera lamarckii) subspecies were compared with their hybrids and backcrosses. The rates of increase in some morphometric characteristics as evidence of hybridization between an Egyptian virgin queen and Carniolan drones being 1.7, 3.2, 0.15, 0.5. 2.4, 0.33 and 1.43 percent for forewing length, width, ovariole number, spermatheca diameter, third tergit length, width, and fourth tergit length. Moreover, the backcross generation showed reductions for all queen characteristics resulting from hybridization between an Egyptian virgin queen and Carniolan drones being 2.35, 4.058.6, 3.1, 0.93,4.2, 1.04, 0.34,and 11.5% for forewing width, ovariole number, spermatheca diameter, third tergit length, third tergit width, fourth tergit length, fourth tergit width and for queen weight.