Phylogenetic variations in a novel family of hyperstable apple snail egg proteins: insights into structural stability and functional trends.

The relationship between protein stability and functional evolution is little explored in proteins purified from natural sources. Here, we investigated a novel family of egg proteins (Perivitellin-1, PV1) from Pomacea snails. Their remarkable stability and clade-related functions in most derived clades (Canaliculata and Bridgesii) make them excellent candidates for exploring this issue. To that aim, we studied PV1 (PpaPV1) from the most basal lineage, Flagellata. PpaPV1 displays unparalleled structural and kinetic stability, surpassing PV1s from derived clades, ranking among the most hyperstable proteins documented in nature. Its spectral features contribute to a pale egg coloration, exhibiting a milder glycan binding lectin activity with a narrower specificity than PV1s from the closely related Bridgesii clade. These findings provide evidence for substantial structural and functional changes throughout the genus' PV1 evolution. We observed that structural and kinetic stability decreased in a clade-related fashion and was associated with large variations in defensive traits. For instance, pale PpaPV1 lectin turns potent in the Bridgesii clade, adversely affecting gut morphology, while giving rise to brightly colored PV1s providing eggs with a conspicuous, probably warning signal in the Canaliculata clade. This work provides a comprehensive comparative analysis of PV1s from various apple snail species within a phylogenetic framework, offering insights into the interplay among their structural features, stability profiles and functional roles. More broadly, our work provides one of the first examples from natural evolution showing the crucial link among protein structure, stability and evolution of new functions.

Accumulation of trace metals in eggs and hatchlings of Chelonia mydas.

BACKGROUND: The objective of this study was to verify the accumulation of trace metals in eggs and hatchlings of Chelonia mydas, evaluating if metal accumulation is originated from maternal transfer and/or from the incubation environment. Other assessments were also performed, as metal distribution in different tissues (blood, kidney, liver, muscle, and turtle shells) of newly hatched turtles, and genotoxic analysis, to verify possible damages caused by the presence of metals. METHODS: The assessments were carried out by quantifying Cd, Ni, Pb, Mn and Fe in egg sample collected during laying time (eggshells (ELT) and egg content (EC)), eggshells from newly hatched turtles (ENH), hatchlings tissues (H - blood, kidney, liver, muscle, and shell)) (n = 18 for each biological sample - 3 of each nest) and nest sediments (n = 6, one of each nest). Comparative analysis were made between ELT and ENH, as well as between egg content (EC) and the sum of tissue samples from hatchlings, using Mann-Whitney hypothesis test (p < 0,05). The amount of metals in different hatchling was quantified and followed by the Dunn post-test. A principal component analysis (PCA) was also employed. RESULTS: Metals studied were found in all investigated samples. The concentration of a great amount of investigated metals was significantly higher (P=<0.001) in eggshells from ENH than in ELT. An increase in Cd (2.16-fold), Pb (3.47-fold), Fe (6.83-fold) and Mn (195.57-fold) concentration was noticed in ENH. We also observed an increase in Fe (1.59-fold), Mn (1.74-fold) and Ni (1.59-fold) concentration in hatchling, when compared with EC, due to transfer from nest sediments. In relation to the hatchling's tissues, blood was shown to accumulate higher concentrations of Ni and Pb, while shells accumulated more Cd and Fe, and Mn is more associated with liver and kidney. Fe was the highest accumulated metal in both tissues, and muscles presented discrete concentrations of Ni, Mn, and Pb. A mean concentration of 1.25‰ MN was obtained in C. mydas hatchlings, indicating that the accumulation of metals in hatchlings didn't cause toxicology effects. CONCLUSION: Hatchlings accumulate metals through the maternal and sediment transfer, although the levels of metal accumulation were not enough to cause genotoxic damage.

Kairomones from Euschistus heros egg masses and their potential use for Telenomus podisi parasitism improvement.

Telenomus podisi Ashmead (Hymenoptera: Scelionidae) is the most important egg parasitoid of Euschistus heros (Fabricius) (Hemiptera: Pentatomidae), and its successful parasitism is related to their searching ability to find suitable hosts under a complex chemical environment using host-reliable cues. Thus, the objective of this study was to elucidate chemical substances on the external layer of E. heros eggs and report its potential kairomonal activity on T. podisi. We tested female wasps in olfactometer system to synthetic compounds obtained from a chemical identification of E. heros egg masses. The synthetic blend was also evaluated in parasitism tests under laboratory and semi-field conditions. We identified 31 substances from egg surface extracts, including monoterpenes, aldehydes and alkanes. Among those compounds, a synthetic solution including camphene, ß-pinene, limonene and benzaldehyde-induced chemotaxic behaviour on the wasps and increased the parasitism on E. heros eggs, either in laboratory or semi-field test, suggesting its potential use to T. podisi manipulation and parasitism improvement.

Residual vitellus and energetic state of wolf spiderlings Pardosa saltans after emergence from egg-sac until first predation.

The aim of this study was to evaluate energetic source used by juveniles of a terrestrial oviparous invertebrate during the earliest periods of their life. Growth, behavioural activities and energy contents of Pardosa saltans spiderlings' residual vitellus were monitored during 8 days after their emergence from their egg-sac until they disperse autonomously. The life-cycle of juvenile after emergence can be divided into three periods: a gregarious while juveniles are aggregated on their mother, dismounting off their mother's back and dispersion. We present the first biochemical study of residual vitellus and energy expenditure during these three periods. At emergence, the mean weight of juveniles was 0.59 mg and energy stock from residual vitellus averaged 51 cal/g wet mass. During gregarious period, the weight of the juveniles aggregated on their mother did not vary significantly and juveniles utilized only 1 cal/day from their residual vitellus. During the period from dismounting until their first exogenous feed, juveniles lost weight and used 30% of their residual vitellus stock. Proteins from the residual vitellus contributed principally to their energy expenditure during this period: 1.5 µg protein/day. Juveniles' first exogenous feeding was observed 7-8 days after emergence, when 70% of residual vitellus energy had been utilized. Juveniles dispersed after eating, reconstituting an energy stock comparable to that observed at emergence from egg-sac (50 cal/g wet mass). This new energy stock contains mainly lipids unlike the energy stock from the residual vitellus.

Accumulation of trace elements in leatherback turtle (Dermochelys coriacea) eggs from the south-western Caribbean indicates potential health risks to consumers.

Trace metal and metalloid levels were measured in eggs of the NW Atlantic leatherback turtle (Dermochelys coriacea) from nesting grounds in the Bocas del Toro province, Panama, to infer exposure and associated risks to local communities. Samples were analyzed for a set of 26 essential and non-essential elements using inductively coupled plasma techniques. Median concentrations of Fe, Zn, As, Se and Sr in D. coriacea eggs were higher than previously reported for this species, which likely reflects differential contamination levels of specimens during foraging. The evaluation of non-carcinogenic human health risks from ingesting leatherback eggs has revealed potential deleterious effects due to high concentrations of As, Se and Sr for all examined age and gender groups, while Hg and Zn levels were above international standards for children. Hazard index (HI) values exceeded unity in all cases indicating serious health impacts related to possible additive effects of multiple metals co-occurring in the eggs. Our findings suggest that exposure to high (inorganic) As and Cr(VI) levels is associated with an increased carcinogenic risk, significantly exceeding the acceptable lifetime risk of 10-6 for both adults and children. Despite some limitations, such as unclear As and Cr speciation, our results demonstrated that the ingestion of D. coriacea eggs poses considerable health risks to local communities, and their consumption should not exceed 3.4 × 10-4 g (5.0 × 10-6 eggs) kg BW d-1. Resource managers and conservationists should focus their attention to human health effects as an alternative tool to address egg poaching and consumption.

Effects of Phytase Inclusion in Broiler Breeder Diets During Early Lay on their Fecal and Egg Characteristics

This study investigated the effects of phytase inclusion in broiler breeder diets on fecal and egg characteristics. A total of 48 female broiler breeders were evaluated in this study from 21 to 31 weeks of age. The dietary treatments were fed from 30 to 31 wks of age, and included a Positive Control (PosCon) diet, containing 3.0% calcium and 0.50% available phosphorus (AvP); a Negative Control (NegCon) diet, with 3.0% calcium and 0.25% AvP; Negative Control diet + 275 FTU/kg phytase (NegCon+275), and Negative control diet + 550 FTU/kg phytase (NegCon+550). Egg, yolk, albumin, and eggshell weight, albumin height, and eggshell thickness were measured. Fecal parameters included fecal moisture, liquid portion, and mineral content. After 14 d on the experimental diets during the onset of lay, the NegCon+550 diet increased (p 0.01) fecal moisture content. In general, hens fed the highest enzyme level (NegCon+550) excreted fewer (p 0.05) divalent and trivalent cations, which included Al, Fe, Mg, Mn, and Zn. Fecal Na and K levels were not affected by dietary treatments. The NegCon+550 diet increased fecal P when compared with the NegCon and the NegCon+275 diets. The NegCon+550 and PosCon diets exhibited similar fecal P. No significant effects on egg characteristics were observed. It was concluded that during early lay, various signs of fecal changes would probably be observed at phytase dosages above approximately 500 FTU/kg characterized by increased fecal moisture content and excretion of P in broiler breeders.(AU)

Effects of Phytase Inclusion in Broiler Breeder Diets During Early Lay on their Fecal and Egg Characteristics

This study investigated the effects of phytase inclusion in broiler breeder diets on fecal and egg characteristics. A total of 48 female broiler breeders were evaluated in this study from 21 to 31 weeks of age. The dietary treatments were fed from 30 to 31 wks of age, and included a Positive Control (PosCon) diet, containing 3.0% calcium and 0.50% available phosphorus (AvP); a Negative Control (NegCon) diet, with 3.0% calcium and 0.25% AvP; Negative Control diet + 275 FTU/kg phytase (NegCon+275), and Negative control diet + 550 FTU/kg phytase (NegCon+550). Egg, yolk, albumin, and eggshell weight, albumin height, and eggshell thickness were measured. Fecal parameters included fecal moisture, liquid portion, and mineral content. After 14 d on the experimental diets during the onset of lay, the NegCon+550 diet increased (p 0.01) fecal moisture content. In general, hens fed the highest enzyme level (NegCon+550) excreted fewer (p 0.05) divalent and trivalent cations, which included Al, Fe, Mg, Mn, and Zn. Fecal Na and K levels were not affected by dietary treatments. The NegCon+550 diet increased fecal P when compared with the NegCon and the NegCon+275 diets. The NegCon+550 and PosCon diets exhibited similar fecal P. No significant effects on egg characteristics were observed. It was concluded that during early lay, various signs of fecal changes would probably be observed at phytase dosages above approximately 500 FTU/kg characterized by increased fecal moisture content and excretion of P in broiler breeders.

Structure and ligand binding of As-p18, an extracellular fatty acid binding protein from the eggs of a parasitic nematode.

Intracellular lipid-binding proteins (iLBPs) of the fatty acid-binding protein (FABP) family of animals transport, mainly fatty acids or retinoids, are confined to the cytosol and have highly similar 3D structures. In contrast, nematodes possess fatty acid-binding proteins (nemFABPs) that are secreted into the perivitelline fluid surrounding their developing embryos. We report structures of As-p18, a nemFABP of the large intestinal roundworm Ascaris suum, with ligand bound, determined using X-ray crystallography and nuclear magnetic resonance spectroscopy. In common with other FABPs, As-p18 comprises a ten ß-strand barrel capped by two short α-helices, with the carboxylate head group of oleate tethered in the interior of the protein. However, As-p18 exhibits two distinctive longer loops amongst ß-strands not previously seen in a FABP. One of these is adjacent to the presumed ligand entry portal, so it may help to target the protein for efficient loading or unloading of ligand. The second, larger loop is at the opposite end of the molecule and has no equivalent in any iLBP structure yet determined. As-p18 preferentially binds a single 18-carbon fatty acid ligand in its central cavity but in an orientation that differs from iLBPs. The unusual structural features of nemFABPs may relate to resourcing of developing embryos of nematodes.

In ovo injection of ascorbic acid and higher incubation temperature modulate blood parameters in response to heat exposure in broilers.

1. This study analysed whether in ovo injection of ascorbic acid before incubation and at high incubation temperature influenced blood characteristics and performance in broilers reared in different temperature conditions. 2. A total of 3,000 fertile eggs from broiler breeders (Cobb®) were randomly divided into three incubation treatments: no ascorbic acid injection and egg incubation at 37.5°C (control); no ascorbic acid injection and egg incubation at 39°C; in ovo ascorbic acid injection prior to incubation (6 µg AA/100 µl water) and egg incubation at 39°C. 3. Male chicks hatched from the three incubation treatments were submitted to three distinct rearing temperatures (control, cold and hot) from the third week of age onwards (540 chicks were divided into 6 treatments with 5 replicates per treatment). 4. Measurements at 42 d showed that, after egg incubation at 39°C, the haematocrit, haemoglobin values, ionised calcium and glucose concentrations were increased and base excess values were reduced. However, in ovo injection of ascorbic acid normalised all these parameters. 5. Partial CO2 and O2 pressure were higher with increased rearing temperature. Blood pH was lower when eggs were incubated at 39°C and injected with ascorbic acid. In ovo injection of ascorbic acid induced leucocytosis due to lymphocytosis and heterophilia, restored basophils rate and led to monocytopoenia. Leucocytosis was triggered by hot rearing temperature due to lymphocytosis, eosinophilia and heterophilia. 6. The results obtained in this study showed that in ovo injection of ascorbic acid before incubation may serve as a long-term stimulator and modulator of the broiler immune system, and that high incubation temperatures induce adaptations in the electrolytic balance, minimising or avoiding the occurrence of respiratory alkalosis under hot rearing temperature.

Conditioning Native Telenomus and Trissolcus (Hymenoptera: Scelionidae) Egg Parasitoids to Recognize the Exotic Brown Marmorated Stink Bug (Heteroptera: Pentatomidae: Halyomorpha halys).

Halyomorpha halys (Stål) (Heteroptera: Pentatomidae), the brown marmorated stink bug (BMSB), is a polyphagous fruit and vegetable pest from eastern Asia and now invasive in the United States and Europe. Earlier research revealed that the main volatile from hexane egg extracts of a western North American pentatomid, Euschistus conspersus Uhler, to which two native scelionid egg parasitoids, Telenomus podisi Ashmead and Trissolcus erugatus Johnson are highly attracted, was methyl (2E,4Z)-2,4-decadienoate, the major component of the conspecific male-produced aggregation pheromone. Conversely, extracts of BMSB eggs lacked the male-produced sesquiterpenoid H. halys pheromone components but contained C16,18,20 aldehydes (hexadecanal, octadecanal, and eicosanal); both egg-surface extracts of BMSB eggs and the C16,18,20 synthetic aldehyde blend repelled the female parasitoids. The goal of the present research was to manipulate egg-surface volatiles to induce the scelionid egg parasitoids to adopt BMSB eggs as a host. Here it was demonstrated that individual females of both parasitoids could be conditioned to H. halys egg-surface aldehydes in Y-tube olfactometer experiments, and this positive memory lasted 3-4 d. Furthermore, conditioned wasps successfully parasitized fresh H. halys eggs in no choice tests, and their offspring continued to successfully parasitize fresh H. halys eggs for 2-3 more generations. Eventually, both the individual and generational memories faded. Unconditioned female parasitoids were not attracted to H. halys egg extract or the synthetic blend of egg-surface aldehydes, nor did they parasitize BMSB eggs. Theoretical and practical implications of the research are discussed in the contexts of Hopkins' host selection principle, biological control, and instinct evolution.

Comparing the metallic elemental compositions of Kelp Gull Larus dominicanus eggs and eggshells from the Swartkops Estuary, Port Elizabeth, South Africa.

Metals attributed to pollution may increase their concentrations above the geological background and pose toxic challenges towards humans and biota. We analysed sixteen Kelp Gull eggs and eggshells for 30 metallic elements from the Swartkops Estuary (SE), an important recreational, industrial, and ecological asset for Port Elizabeth, the region, and South Africa. Mean concentrations for eggshell and egg content for Hg was 0.02 and 0.4 mg/kg dm, Cr was 4 and 18 mg/kg dm (the highest yet recorded for any gull or tern egg), for Zn 2.1 and 62 mg/kg dm, for Sr 880 and 12 mg/kg dm, for V 170 and 1.3 mg/kg dm, and for Co 1.7 and 0.002 mg/kg dm, respectively. Zinc, Se, and Hg, increased on a dry-mass basis from sediment via small fish to gull egg content, indicating bioaccumulation. No effect on eggshell thickness was seen. We also determined that eggshell concentrations cannot be used as a proxy for egg content concentrations. Mercury, Cr, V, Co, and Zn were elements we identified as potentially problematic that require source identification and mitigation. Further research into other high-trophic animals such as herons, egrets, cormorants, and otters in the SE system is proposed.

Organochlorines Contaminants in Eggs of Hawksbill (Eretmochelys imbricata) and Green Sea Turtles (Chelonia mydas) from Mexico coast.

The investigation of organochlorine pesticides (OCPs) levels in sea turtles is an important issue in conservation research, due to the harmful effects of these chemicals. In the present study, OCPs concentrations were determined in the eggs of two sea turtle species (Eretmochelys imbricata and Chelonia mydas) collected from the Punta Xen and Isla Aguada (Mexican coast) in 2014 and 2015. Concentrations of 20 OCPs were analysed, including isomers of hexachlorocyclohexane, aldrin, chlordanes, endosulfans, methoxychlor, DDTs, and heptachlor. From the group of contaminants considered (analysed as families), the results revealed higher concentrations of ΣHCH and ΣDienes on both selected species. We analysed the relationship between turtle size and the OCPs concentrations; no correlation was found between the size of the female and concentrations in the eggs. In addition, principal component analysis indicated pattern differences between species and years, in good agreement with concentrations differences.

Physical-Chemical and Sensorial Quality of Eggs Coated With Copaiba Oil Biofilm and Stored At Room Temperature for Different Periods

The present study aimed at evaluating the effects of a coating based on copaiba oil on the quality of eggs stored for different periods. Eggs were coated with copaiba oil solutions (4, 8, 12, 16, or 20% copaiba oil) or not (control) and stored for 1, 7, 14, 21, 28 or 35 days at room temperature. The following parameters were evaluated: egg weight loss, egg components (albumen, yolk, and eggshell) relative weights, egg specific gravity, Haugh units, eggshell quality, and sensorial attributes. Eggs stored for 35 days presented the highest weight losses. Coating (20% copaíba oil solution) reduced egg weight loss up to 41.02%. Coated eggs presented better internal quality (yolk and albumen heights, specific gravity, and eggshell strength). Sensorial attributes were negatively affected by storage time (aroma and flavor), and copaiba oil solution (aroma, appearance, and flavor), with the natural odor of copaiba described by the tasters. Egg internal, external, and sensorial quality worsened with storage time. Solutions containing 16 and 20% copaiba oil can be used as a biofilm to coat eggs, preserving its internal and external quality, and may affect their sensory characteristics, and therefore, may be a viable alternative for maintaining the internal quality of eggs stored at room temperature for long periods.(AU)

Effect of In Ovo Feeding of L-Glutamine to Chick Embryos

In ovo feeding (IOF), injecting nutrients into the amnion of the avian embryo may enhance hatchability, gastrointestinal development and serum metabolism changes. This hypothesis was evaluated with 5 IOF solutions containing L-glutamine. Were used 315 fertile Rhode Island Red eggs were used (breeders with 32-weeks). The experimental design was completely randomized with the treatments constituted by two controls and five solutions containing L-glutamine levels with 45 replicates each. Data collected were subjected to polynomial regression at 5% of significance. Differences (p>0.05) were observed in hatchability and intermediary mortality, with a gradual lower of decrease in hatchability from the IOF of L-glutamine. The yolk sac was higher (p 0.05) after the IOF (control and L-glutamine) in the in ovo fed embryos at 0.5% L-glutamine. IOF of L-glutamine alone enhanced the blood pH and reduced the other serum parameters (p 0.05), which may have fuelled more embryo development, mainly vital organs how as the heart and the liver due to the larger concentration of available nutrients for the embryo. The results of this study indicate that until 0.5% L-glutamine may be supplemented in-ovo to chick embryos without negative influence on chick weight and gastrointestinal tract development, acting as serum biochemical metabolism regulator and obtaining better hatchability.(AU)

Physical-Chemical and Sensorial Quality of Eggs Coated With Copaiba Oil Biofilm and Stored At Room Temperature for Different Periods

The present study aimed at evaluating the effects of a coating based on copaiba oil on the quality of eggs stored for different periods. Eggs were coated with copaiba oil solutions (4, 8, 12, 16, or 20% copaiba oil) or not (control) and stored for 1, 7, 14, 21, 28 or 35 days at room temperature. The following parameters were evaluated: egg weight loss, egg components (albumen, yolk, and eggshell) relative weights, egg specific gravity, Haugh units, eggshell quality, and sensorial attributes. Eggs stored for 35 days presented the highest weight losses. Coating (20% copaíba oil solution) reduced egg weight loss up to 41.02%. Coated eggs presented better internal quality (yolk and albumen heights, specific gravity, and eggshell strength). Sensorial attributes were negatively affected by storage time (aroma and flavor), and copaiba oil solution (aroma, appearance, and flavor), with the natural odor of copaiba described by the tasters. Egg internal, external, and sensorial quality worsened with storage time. Solutions containing 16 and 20% copaiba oil can be used as a biofilm to coat eggs, preserving its internal and external quality, and may affect their sensory characteristics, and therefore, may be a viable alternative for maintaining the internal quality of eggs stored at room temperature for long periods.

Effect of In Ovo Feeding of L-Glutamine to Chick Embryos

In ovo feeding (IOF), injecting nutrients into the amnion of the avian embryo may enhance hatchability, gastrointestinal development and serum metabolism changes. This hypothesis was evaluated with 5 IOF solutions containing L-glutamine. Were used 315 fertile Rhode Island Red eggs were used (breeders with 32-weeks). The experimental design was completely randomized with the treatments constituted by two controls and five solutions containing L-glutamine levels with 45 replicates each. Data collected were subjected to polynomial regression at 5% of significance. Differences (p>0.05) were observed in hatchability and intermediary mortality, with a gradual lower of decrease in hatchability from the IOF of L-glutamine. The yolk sac was higher (p 0.05) after the IOF (control and L-glutamine) in the in ovo fed embryos at 0.5% L-glutamine. IOF of L-glutamine alone enhanced the blood pH and reduced the other serum parameters (p 0.05), which may have fuelled more embryo development, mainly vital organs how as the heart and the liver due to the larger concentration of available nutrients for the embryo. The results of this study indicate that until 0.5% L-glutamine may be supplemented in-ovo to chick embryos without negative influence on chick weight and gastrointestinal tract development, acting as serum biochemical metabolism regulator and obtaining better hatchability.

Albendazole treatment in laying hens: Egg residues and its effects on fertility and hatchability.

This work characterized the egg residual concentrations of albendazole (ABZ) and its sulphoxide (ABZSO) and sulphone (ABZSO2 ) metabolites and evaluated their effect on egg fertility and hatchability after ABZ treatments to laying hens. Seventy hens were allocated in groups: Group-1 was the control without treatment; Group-2 received a single ABZ oral dose (10 mg/kg); Group-3, -4 and -5 were treated with ABZ in medicated feed over 7 days at 10, 40, or 80 mg kg-1  day-1 , respectively. Eggs were analyzed to determine the ABZ/metabolite level by HPLC or subjected to incubation to evaluate the fertility and hatchability. Only ABZSO and ABZSO2 metabolites were quantified in egg after ABZ single oral administration with maximum concentrations of 0.47 ± 0.08 and 0.30 ± 0.07 µg/ml, respectively. ABZ and its metabolites were found in eggs after 7-day ABZ treatments. The egg residue exposure estimated as AUCs (areas under the concentration vs. time curve) were 100.5 (ABZ), 56.3 (ABZSO) and 141.3 µg hr g-1 (ABZSO2 ). ABZ administration did not affect the egg fertility at any dosages. Egg hatchability was not affected by ABZ treatment at 10 mg/kg in medicated feed, but it decreased when the dose was 4-8 times higher. These results should be considered when ABZ is used for deworming laying hens.

Is It Possible to Manipulate Scelionidae Wasps' Preference to a Target Host?

Parasitoid host selection is mainly mediated by chemical cues, which can be adjusted by experience, changing their innate behavior. Therefore, this study evaluated if immature experience (pre-imaginal conditioning) on eggs and volatiles from different host eggs has influence on parasitism and chemotaxic behavior of Telenomus podisi Ashmead and/or Trissolcus basalis Wollaston (Hymenoptera: Scelionidae). Both wasp species were submitted to a multiple-choice parasitism test among Euschistus heros (Fabricius), Piezodorus guildinii (Westwood), and Nezara viridula L. (Hemiptera: Pentatomidae) (Hemiptera: Pentatomidae) egg masses. Eggs from these three stink bugs were equally offered to female parasitoids. After that, adults which emerged from each host were also exposed to parasitism in a multiple-choice test for up to an additional generation. Moreover, in olfactometer "Y," the behavior of innate and experienced T. podisi females to volatiles from hosts' egg extracts was tested, to study their learning and memory ability. The original host had influence on T. podisi parasitism; however, T. basalis always parasitized more N. viridula eggs independently of its last rearing host. Innate T. podisi females responded positively to E. heros and P. guildinii egg volatiles, but this behavior was not observed in N. viridula. When T. podisi females were experienced on egg volatiles from a new host, they showed significant learning and memory ability for the specific host volatile for, at least, 24 h. Experienced wasps responded positively to N. viridula and through this result we have evidences about the possibility to manipulate wasp's preferences to a specific target host.

Morphodifferentiation of Gené's organ in engorged Amblyomma sculptum Berlese, 1888 female ticks (Acari: Ixodidae).

The Gené's organ (GO) secretes a waxy substance on eggs that reduces water loss and has antimicrobial properties. The current study evaluated morphological and histochemical aspects of GO in Amblyomma sculptum from the period of post-feeding - when ticks detach from the host - to the stage just before oviposition. In this species, GO is composed of a corpus and two pairs of glands, namely, cranial and caudal. Glandular cells are joined laterally by a system of interdigitating membranes with junctional complexes. Histochemistry showed that lipid droplets became more evident as GO developed, while glycogen gradually disappeared, and proteins were detected only near the onset of oviposition. The ultrastructural results revealed a marked distension of the cuticle filled with an amorphous material. Glandular cells showed poor endoplasmatic reticulum, many mitochondria mainly in the basal cell poles and a very developed basal labyrinth. We concluded that the development of GO in A. sculptum ticks was continuous and progressive, and it started after detachment from the host. Additionally, the ultrastructure study suggests that gland cells have an important absorption ability and a low synthetic activity, which indicates that the majority of wax precursors are derived from haemolymph.

Darker eggs of mosquitoes resist more to dry conditions: Melanin enhances serosal cuticle contribution in egg resistance to desiccation in Aedes, Anopheles and Culex vectors.

Mosquito vectors lay their white eggs in the aquatic milieu. During early embryogenesis water passes freely through the transparent eggshell, which at this moment is composed of exochorion and endochorion. Within two hours the endochorion darkens via melanization but even so eggs shrink and perish if removed from moisture. However, during mid-embryogenesis, cells of the extraembryonic serosa secrete the serosal cuticle, localized right below the endochorion, becoming the third and innermost eggshell layer. Serosal cuticle formation greatly reduces water flow and allows egg survival outside the water. The degree of egg resistance to desiccation (ERD) at late embryogenesis varies among different species: Aedes aegypti, Anopheles aquasalis and Culex quinquefasciatus eggs can survive in a dry environment for ≥ 72, 24 and 5 hours, respectively. In some adult insects, darker-body individuals show greater resistance to desiccation than lighter ones. We asked if egg melanization enhances mosquito serosal cuticle-dependent ERD. Species with higher ERD at late embryogenesis exhibit more melanized eggshells. The melanization-ERD hypothesis was confirmed employing two Anopheles quadrimaculatus strains, the wild type and the mutant GORO, with a dark-brown and a golden eggshell, respectively. In all cases, serosal cuticle formation is fundamental for the establishment of an efficient ERD but egg viability outside the water is much higher in mosquitoes with darker eggshells than in those with lighter ones. The finding that pigmentation influences egg water balance is relevant to understand the evolutionary history of insect egg coloration. Since eggshell and adult cuticle pigmentation ensure insect survivorship in some cases, they should be considered regarding species fitness and novel approaches for vector or pest insects control.