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opencc-zeroJun 2020View details →

Data from: Reprograming of epigenetic mechanisms controlling host insect immunity and development in response to egg-laying by a parasitoid wasp

Parasitoids are insects that use other insects as hosts. They sabotage host cellular and humoral defenses to promote the survival of their offspring by injecting viruses and venoms along with their eggs. Many pathogens and parasites disrupt host epigenetic mechanisms to overcome immune system defenses, and we hypothesized that parasitoids may utilize the same strategy. We used the ichneumon wasp Pimpla turionellae as a model idiobiont parasitoid to test this hypothesis, with pupae of the greater wax moth Galleria mellonella as the host. We found that parasitoid infestation involves the suppression of host immunity-related effector genes and the modulation of host genes involved in developmental hormone signaling. The transcriptional reprogramming of host genes following the injection of parasitoid eggs was associated with changes in host epigenetic mechanisms. The introduction of parasitoids resulted in a transient decrease in host global DNA methylation and the modulation of acetylation ratios for specific histones. Genes encoding regulators of histone acetylation and deacetylation were mostly downregulated in the parasitized pupae, suggesting that parasitoids can suppress host transcription. We also detected a strong parasitoid-specific effect on host microRNAs regulating gene expression at the post-transcriptional level. Our data therefore support the hypothesis that parasitoids may favor the survival of their offspring by interfering with host epigenetic mechanisms to suppress the immune system and disrupt development.

opencc-zeroNov 2019View details →

Data from: Sulfoxaflor exposure reduces egg laying in bumblebees (Bombus terrestris)

<ol> <li>Sulfoximine-based insecticides, such as sulfoxaflor, are of increasing global importance and have been registered for use in 81 countries, offering a potential alternative to neonicotinoid insecticides.</li> <li> Previous studies have demonstrated that sulfoxaflor exposure can have a negative impact on the reproductive output of bumblebee colonies, but the specific life-history variables that underlie these effects remain unknown.</li> <li>Here, we used a microcolony-based protocol to assess the sub-lethal effects of chronic sulfoxaflor exposure on egg laying, larval production, ovary development, sucrose consumption, and mortality in bumblebees. Following a pre-registered design, we exposed colonies to sucrose solutions containing 0, 5, 10 and 250ppb of sulfoxaflor. Exposure at 5ppb has been previously shown to negatively impact colony reproductive success.</li> <li>Our results showed that sulfoxaflor exposure at 5ppb (lowest exposure tested) reduced the number of eggs found within the microcolonies (Hedge's d = -0.37), with exposed microcolonies also less likely to produce larvae (Hedge's d = -0.36). Despite this, we found no effect of sulfoxaflor exposure on ovarian development. Sulfoxaflor-exposed bumblebees consumed less sucrose solution, potentially driving the observed reduction in egg laying.</li> <li> Policy implications. Regulatory bodies such as the European Food Safety Authority (EFSA) are under increasing pressure to consider the potential impact of insecticides on wild bees, such as bumblebees, but sublethal effects can go undetected at lower-tier testing. In identifying just such an effect for bumblebees exposed to sulfoxaflor, this study highlights that microcolony-based protocols are a useful tool that could be implemented within an ecotoxicology framework. Furthermore, the results provide evidence for potentially negative consequences of pollinator exposure to an insecticide that is currently undergoing the licensing process in several EU member states.</li> </ol>

opencc-zeroMar 2020View details →

Egg laying behavior of the common cuckoo (Cuculus canorus): data based on field video-recordings

The egg laying behavior of brood parasites is at the heart of studies on their co-evolution with hosts. Updating and reporting more egg laying behavior can improve our perception and insight on the brood parasitism process. During a 7 years' study period, we monitored 455 Oriental reed warbler (Acrocephalus orientalis) nests during the egg laying period, of which 250 were parasitized by common cuckoos (Cuculus canorus). We randomly recorded 53 clear videos of cuckoo parasitism, analyzed and recorded all parasitic behavior of cuckoo in details, summarized the process of brood parasitism displayed by the common cuckoo. Based on analyses of these field video-recordings, we proposed a new explanation for the egg removal behavior, namely the delivery hypothesis, i.e. the egg pecking and biting may help parasitic cuckoos lay eggs faster, thereby avoiding the host's attention and reducing host attacks, whilst egg removal is the side effect of egg pecking and biting. We concluded that common cuckoos do not care whether the host is around the nest, as they have a set of methods to deal with host attacks and can complete parasitism boldly and smoothly at any time.

opencc-zeroDec 2011View details →

Data from: The consequences of genetic variation in male sex peptide gene-expression levels for SP retention and egg laying in female Drosophila

The accessory gland proteins (Acps) that male Drosophila melanogaster produce and transfer to females during copulation are key to male and female fitness. One Acp, the sex peptide (SP), is largely responsible for a dramatic increase in female egg laying and decrease in female receptivity after copulation. While genetic variation in male SP expression levels correlate with refractory period duration in females, it is unknown whether male SP expression influences female egg laying or if any effect of SP is mediated by SP retention in the female reproductive tract. Here we measured the amount of SP retained in the female reproductive tract after mating and female egg laying after copulating with virgin males. We found no correlation between male SP expression levels and egg laying, or the amount of SP in the female reproductive tract after mating. Additionally, the amount of SP retained in the female did not influence egg laying. These finding suggests that additional factors, such as variation in other Acps, are important for the retention of SP in females and its quantitative effects on egg laying. It also shows that egg laying and refractory period response to SP is at least partially uncoupled.

opencc-zeroDec 2011View details →

Data from: A treefrog with reproductive mode plasticity reveals a changing balance of selection for non-aquatic egg-laying

Non-aquatic reproduction has evolved repeatedly, but the factors that select for laying eggs on land are not well understood. The treefrog Dendropsophus ebraccatus has plasticity in reproductive mode, laying eggs that successfully develop in or out of water. This permits the first experimental comparison of the selective agents that shape adult oviposition behavior and embryo developmental capacity. I quantified the sources and strength of arboreal and aquatic egg mortality, how mortality varies with weather patterns, and assessed 39 years of daily rainfall patterns to infer historic levels of egg mortality and effects of climate change on the selective balance between aquatic and non-aquatic egg deposition. Aquatic predators and desiccation were the strongest selective agents in water and air, respectively. Egg mortality varied with weather such that aquatic oviposition was advantageous when rainfall was low, but laying eggs out of water increased survival when rainfall was high. Additionally, I found that since 1972 there have been significant changes in the patterns of rainfall in central Panama, which has altered the selective landscape acting on egg-laying behavior. This work provides insight into both the evolution and maintenance of adaptive phenotypic plasticity as well as historic and current selection on reproduction.

opencc-zeroDec 2014View details →

Data from: Oviposition site choice under conflicting risks demonstrates that aquatic predators drive terrestrial egg-laying

Laying eggs out of water was crucial to the transition to land and has evolved repeatedly in multiple animal phyla. However, testing hypotheses about this transition has been difficult because extant species only breed in one environment. The pantless treefrog, Dendropsophus ebraccatus, makes such tests possible because they lay both aquatic and arboreal eggs. Here, we test the oviposition site choices of D. ebraccatus under conflicting risks of arboreal egg desiccation and aquatic egg predation, thereby estimating the relative importance of each selective agent on reproduction. We also measured discrimination between habitats with and without predators and development of naturally laid aquatic and arboreal eggs. Aquatic embryos in nature developed faster than arboreal embryos, implying no cost to aquatic egg laying. In choice tests, D. ebraccatus avoided habitats with fish, showing that they can detect aquatic egg predators. Most importantly, D. ebraccatus laid most eggs in the water when faced with only desiccation risk, but switched to laying eggs arboreally when desiccation risk and aquatic predators were both present. This provides the first experimental evidence to our knowledge that aquatic predation risk influences non-aquatic oviposition and strongly supports the hypothesis that it was a driver of the evolution of terrestrial reproduction.

Fig. 5 in A new giant egg-laying onychophoran (Peripatopsidae) reveals evolutionary and biogeographical aspects of Australian velvet worms

Fig. 5 Colour pattern variation in Ooperipatellus nickmayeri sp. nov. Images of walking specimens in dorsal view (left) and detail of the corresponding colour pattern along the dorsal midline (right). In all

Fig. 4 in A new giant egg-laying onychophoran (Peripatopsidae) reveals evolutionary and biogeographical aspects of Australian velvet worms

Fig. 4 Karyotype of Ooperipatellus nickmayeri sp. nov. Light micrograph of mitotic chromosomes stained with Giemsa and sorted according to their size and morphology. Inset in the lower right corner

Fig. 3 in A new giant egg-laying onychophoran (Peripatopsidae) reveals evolutionary and biogeographical aspects of Australian velvet worms

Fig. 3 Features associated with female reproductive structures in Ooperipatellus nickmayeri sp. nov. Scanning electron micrographs. In all images, the anterior orientation is at the top of the figure, with posterior at the bottom. a Posterior-most body region bearing a conspicuous ovipositor, which is characteristic of Ooperipatellus. b Detail of the

Fig. 7 in A new giant egg-laying onychophoran (Peripatopsidae) reveals evolutionary and biogeographical aspects of Australian velvet worms

Fig. 7 Cephalic structures in Ooperipatellus nickmayeri sp. nov. Scanning electron micrographs. In all images, the anterior orientation is at the top of the figure, with posterior at the bottom. a Overview of the head. The lack of sclerotized/eversible head organs and/or modified head papillae is a characteristic feature of Ooperipatellus. Arrow points to remnant of ejected slime on the head of the specimen. b Detail of

opencc-zeroDec 2017View details →

Data from: Thick eggshells of brood parasitic cowbirds protect their eggs and damage host eggs during laying

Brood parasites lay thick-shelled eggs and numerous hypotheses have been proposed to explain the significance of this trait. We examined whether thick eggshells protect the parasite egg during laying events. We used eggs of the parasitic shiny cowbird (Molothrus bonariensis) and its hosts, the house wren (Troglodytes aedon) and chalk-browed mockingbird (Mimus saturninus) in South America and the eggs of the parasitic brown-headed cowbird (M. ater) and its hosts the house wren and red-winged blackbird (Agelaius phoeniceus) in North America. We experimentally dropped parasite eggs onto host eggs to simulate laying by the parasite, parasite eggs onto parasite eggs to simulate multiple parasitism, host eggs onto parasite eggs to simulate hosts laying from the height cowbirds lay, and stirred eggs to simulate jostling that may occur when cowbirds and hosts interact during laying events. We found that cowbird eggs were significantly less likely to be damaged than host eggs when they were laid onto a host egg and when host and cowbird eggs were laid onto them. There was minimal damage to eggs during jostling experiments, thereby failing to support the hypothesis that thick eggshells provide protection when eggs are jostled. These findings support the hypotheses that thick eggshells resist damage when laid from an elevated position, when additional cowbird eggs are laid onto them in multiply parasitized nests, and these eggs also damage host eggs when laid.

Figure 5 in Habitat, egg-laying behaviour, eggs and tadpoles of four sympatric species of Pseudopaludicola (Anura, Leiuperidae)

Figure 5. Oral discs of the tadpoles of Pseudopaludicola and Physalaemus. (A) Pseudopaludicola saltica, (B) Pseudopaludicola mystacalis, (C) Pseudopaludicola ternetzi, (D) Most common pattern of Pseudopaludicola aff. canga, (E) Physalaemus cuvieri and (F) Physalaemus centralis. Specimens from Uberlândia, MG, Brasil. Diagrams and scale shown in Figure 4.

Figure 2 in Habitat, egg-laying behaviour, eggs and tadpoles of four sympatric species of Pseudopaludicola (Anura, Leiuperidae)

Figure 2. An egg clutch of Pseudopaludicola saltica. Individual eggs (arrows) can be seen as the spheres covered with sand grains. Scale about 15 mm.

Figure 1 in Habitat, egg-laying behaviour, eggs and tadpoles of four sympatric species of Pseudopaludicola (Anura, Leiuperidae)

Figure 1. Egg-releasing behaviour of two Pseudopaludicola species. Upper panel, an amplectant pair of Pseudopaludicola saltica. The female has her front and hind limbs extended and the male has his feet close to their cloacae; note also that the oviposited eggs are within a circle around the couple (arrows); the egg jelly layers were not yet hydrated. This couple was laying eggs in water about 5 mm deep. Lower panel, an amplectant pair of Pseudopaludicola mystacalis. The couple is completely underwater, the female has her hind legs a little bit extended and the male has his feet in close contact with their cloacae.

Figure 4 in Habitat, egg-laying behaviour, eggs and tadpoles of four sympatric species of Pseudopaludicola (Anura, Leiuperidae)

Figure 4. Diagram of the oral apparatuses of the studied Pseudopaludicola and Physalaemus tadpoles. (A) Pattern found in Pseudopaludicola saltica, Pseudopaludicola mystacalis, Pseudopaludicola ternetzi and a few Pseudopaludicola aff. canga. (B) Most common pattern found in most Pseudopaludicola aff. canga. (C) Pattern found in both Physalaemus cuvieri and Physalaemus centralis. Specimens from Uberlândia, MG, Brasil. Corresponding pictures in Figure 5.

Figure 3 in Habitat, egg-laying behaviour, eggs and tadpoles of four sympatric species of Pseudopaludicola (Anura, Leiuperidae)

Figure 3. Left side view of the tadpole of the Pseudopaludicola species studied. (A) Pseudopaludicola saltica, (B) Pseudopaludicola mystacalis, (C) Pseudopaludicola aff. canga, (D) Pseudopaludicola ternetzi. Specimens from Uberlândia, MG, Brazil. Scales 11.5, 9.0, 10.0 and 10.0 mm for A, B, C and D, respectively.

opencc-zeroOct 2021View details →

Varying digestible isoleucine level to determine effects on performance, egg quality, serum biochemistry, and ileal protein digestibility in diets of young laying hens

To ascertain an appropriate level of isoleucine for LSL-LITE layers (23- to 30-week-old), diets containing total isoleucine concentrations (levels) of 0.66 (Control), 0.69, 0.72, 0.75, 0.78, 0.81, and 0.84% were fed as 7 treatments (2730 kcal/kg metabolizable energy) x 7 replicates x 10 birds per replicate. Significance for performance, egg quality, serum bioc Level, week, and level*week (L*W) were significant for production, egg mass, and feed intake. Level and week were significant for FCR. Week was significant for weight gain. Level was significant for egg weight, specific gravity, and shell thickness; week was also significant for these external egg parameters as well as shape index and proportional shell thickness. L*W was significant for all except shape index. For internal egg measurements, level was significant for proportional yolk, proportional albumen, yolk index, and yolk:albumen. Week was significant for internal egg parameters while L*W significantly affected Haugh unit, proportional albumen weight, yolk index, albumen index, and yolk color. Level was significant for globulin and glucose in serum. Isoluecine at 0.72%, 0.81% and 0.84% produced the lowest FCR, an important standard in the poultry industry. Considering the low FCR of 1.45 and cost for inclusion as a dietary ingredients, 0.72% isoleucine was chosen for further study.