Egg Sacs Research Articles

Predation of salamander egg sacs by the water strider Gerris (Macrogerris) insularisMotschulsky (Hemiptera: Gerridae)

AbstractWater striders (Hemiptera: Gerridae) are sucking predators that inhabit freshwater and marine environments. They prey mainly on insects that fall on the water surface, but they are also known to feed on amphibian eggs. Here, we report on the predation of egg sacs of Hynobius nigrescens (Caudata: Hynobiidae) by Gerris (Macrogerris) insularis. We observed predation on egg sacs of H. nigrescens by G. insularis at a pond in a mountainous area of Nagano City, Nagano Prefecture, Japan. We also found egg sacs with predation marks probably made by water striders at a pond in the mountainous area of Nishimeya Village, Aomori Prefecture, Japan. Five water striders collected around the preyed egg sacs were identified as G. insularis. We filled three tanks with water and an egg sac, and three water striders that were collected at the site in Nishimeya Village were placed together in each tank. In two tanks, the jelly layer of the egg sac was partially cut in a horizontal manner, while in another tank, the jelly layer was removed on the part of the egg sac exposed on the water surface. Notably, the water striders exhibited predatory behavior only when the jelly layers were removed. Considering the results of the rearing experiment and the predation marks observed in the field, G. insularis is also likely to prey on egg sacs at the site in Nishimeya Village. Our study suggested that predation by G. insularis occurs when eggs are accidentally exposed due to disturbance of the jelly layer.

Exploration of Materials for Three-Dimensional NMR Microcoil Production via CNC Micromilling and Laser Etching.

The excellent versatility of 5-axis computer numerical control (CNC) micromilling has led to its application for prototyping NMR microcoils tailored to mass-limited samples (reducing development time and cost). However, vibrations during 5-axis milling can hinder the creation of complex 3D volume microcoils (i.e., solenoids and saddle coils). To address these limitations, a high-resolution NSCNC ELARA 4-axis milling machine was developed with the extra precision required for making complex 3D volume microcoils. Upon investigating the performance of resonators made with various copper-coated dielectrics, resonators with poly(methyl methacrylate) (PMMA) provided the best SNR/line shape. Thus, complex 1.7 mm microcoil designs were machined from Cu-coated PMMA. A milled 6.4 mm solenoid also provided 6.6× the total carbon signal for a 13C-labeled broccoli seed compared to a commercial inverse 5 mm NMR probe (demonstrating potential for larger coil designs). However, the manufacture of coils <1.7 mm with copper-coated PMMA rods was challenging as ∼0.5 mm of remaining PMMA was needed to retain their structural integrity. To manufacture smaller microcoils, both a solenoid and saddle coil (both with 1 mm O.D., 0.1 mm thick walls) were etched from Cu-coated glass capillaries using a UV picosecond laser that was mounted onto an NSCNC 5-axis MiRA7L. Both resonators showed excellent signal and identified a wide range of metabolites in a 13C-labeled algae extract, while the solenoid was further tested on two copepod egg sacs (∼4 μg of total sample). In summary, the flexibility to prototype complex microcoils in-house allows laboratories to tailor microcoils to specific mass-limited samples while avoiding the costs of cleanrooms.

An extensive review of mutualistic and similar ecological associations involving tarantulas (Araneae: Theraphosidae), with a new hypothesis on the evolution of their hirsuteness

ABSTRACT Mutualistic and similar ecological associations between tarantulas (Mygalomorphae: Theraphosidae) and other animals are reviewed. Such associations are found to occur in at least nine theraphosid subfamilies. We present 63 new cases of theraphosid–anuran associations from 10 countries, documenting these interactions for the first time in Brazil, Chile, the Dominican Republic, and the Philippines. These findings are the first documentation of such associations for 13 theraphosid and 20 anuran taxa. Additionally, we report, for the first time, associations potentially of mutualistic nature between tarantulas and snakes, whip spiders, and harvestmen. Furthermore, we provide new reports of associations with ants and termites. While some of these interactions appear to be merely tolerated cohabitations, those involving anurans and ants seem to be more prevalent and complex, clearly offering benefits for both organisms. Additionally, based on multiple observations and field experiments, we propose a new hypothesis regarding the evolution of hirsuteness in theraphosids as a defensive strategy against predatory ants. This hypothesis supports previous findings that suggest a similar function for urticating setae incorporated into egg sacs and moulting mats. We further document a unique escape strategy against ants in New World arboreal theraphosids. Finally, the possibility of a chemical defence mechanism through specialised epidermal glands in theraphosids is briefly discussed.

Spatial and Seasonal Changes in Microbial Community of Hynobius amjiensis Breeding Pools in a Sphagnum-Dominated Peatland.

Peatlands deliver a variety of beneficial ecosystem services, particularly serving as habitats for a diverse array of species. Hynobius amjiensis is a critically endangered amphibian initially discovered in a Sphagnum-dominated peatland in Anji, China. The unique habitat requirements of H. amjiensis make it highly vulnerable to environmental changes. Here, we investigated the different breeding pools of H. amjiensis in the Sphagnum-dominated peatland (the type locality) for a one-year period to evaluate the interactions among the egg sacs present, water quality, and microbial communities (16S and 18S rRNA gene amplicon). The numbers of egg sacs were higher in the breeding pools located at the marginal area than those at the core area of the peatland. Similarly, the α-diversity of bacteria, fungi, and protists were lower in the core region compared to those at the edge of the peatland, perhaps due to water eutrophication. The microbial communities and water quality differed significantly among breeding pools and sampling months. The simpler microbial networks of the breeding pools in the core wetland may impact the numbers and health of the egg sacs. This study contributes to a better understanding of the effect of water quality on biodiversity in peatlands, and it can also guide regulations for wetland conservation and the protection of endangered species.

Plant-level establishment can result from a single female Acanthococcus lagerstroemiae propagule

Crapemyrtle bark scale (CMBS), Acanthococcus lagerstroemiae (Kuwana) (Hemiptera: Eriococcidae), is a non-native scale insect that has spread throughout many urban areas of the Southeast and Middle Atlantic regions of the United States following its initial detection near Dallas, Texas in 2004, severely reducing the aesthetic value and health of the popular ornamental crapemyrtle tree (Lagerstroemia spp.). We infested crapemyrtles with known numbers of CMBS to determine the minimum number of individuals required for establishment after initial arrival on plants. We also investigated how netting—implemented to understand differences in establishment when scale dispersal and predation are inhibited—influenced population growth. We determined that one female CMBS egg sac can successfully establish a new population ~ 92% of the time and that netting had negligible effects on establishment. Our results underscore the importance of surveying and managing CMBS and scale insects with similar biology when attempting to prevent infestation of nursery stock, which is widely implicated as a vector for long-distance dispersal of scale insects.

First occurrence of the family Botryllophilidae Sars G.O., 1921 (Copepoda, Cyclopoida) in Sicily, central Mediterranean Sea

Abstract A female copepod specimen belonging to the family Botryllophilidae Sars G.O., 1921 was retrieved for the first time in December 2023 from nautical ropes of the tourist marina in Palermo (Cala Marina), near the commercial port of the city. The individual lacks many of the distinctive morpho-anatomical characteristics of the class Copepoda, as usual in cyclopoid parasites. In this group, females typically carry paired multiseriate egg sacs, which are extruded from the genital openings and lead to taxonomic identification. The family is commonly associated with tunicates. There are few reports of commensal and/or parasitic copepods associated with sea squirts in the Mediterranean Sea. This record cannot be treated as a new non-indigenous species for the Italian coasts yet, as there are no extensive studies on the distribution of the taxon.

First Record of Tromatobia sp.1 Associated with the Egg Sacs of Neoscona oaxacensis 2 in Mexico

First Record of Tromatobia sp.1 Associated with the Egg Sacs of Neoscona oaxacensis 2 in Mexico

Contrasting responses of Thermocyclops crassus and T. oithonoides (Crustacea, Copepoda) to thermal stress.

Thermal tolerance is a critical factor influencing the survival of living organisms. This study focuses on the thermal resistance of copepod species, Thermocyclops crassus (Fischer, 1853) and T. oithonoides (Sars G.O., 1863), with overlapping distribution ranges in Europe. Short-term heat shock experiments were conducted to assess the thermal resistance of these copepods, considering various temperature increments and exposure durations. Additionally, the study explored the influence of heat shock on egg sac shedding, a vital indicator of population dynamics. Results indicate that widely distributed T. crassus exhibits higher thermal tolerance compared to narrowly distributed T. oithonoides, with survival rates varying under different heat shock conditions. Furthermore, T. crassus demonstrated a quicker response in dropping egg sacs in response to thermal stress, suggesting a potential adaptive mechanism for the survival of adults. However, rapid egg sac droppings pose high risks for eggs facing unfavorable conditions. T. crassus, inhabiting environments with greater temperature fluctuations such as the littoral and pelagial zones, exhibited better survival mechanisms compared to T. oithonoides, which predominantly resides in the pelagic zone. The findings have implications for understanding copepod responses to global warming and thermal pollution. This research contributes insights into the adaptive strategies of thermophilic copepod species and their ecological consequences.

Influence of egg sacs on the swimming performance of freshwater cyclopoid copepods

Abstract Female cyclopoid copepods carry their embryos in egg sacs that impact swimming performance until nauplii hatch. We studied kinematic parameters and mechanical energy of small routine jumps and large escape jumps of non-egg-carrying (NEC) and egg-carrying (EC) females of Mesocyclops leuckarti and Macrocyclops albidus. The drag and body acceleration costs for EC females of M. leuckarti and M. albidus during routine jumps were 28 and 40%, respectively, higher than those for NEC females moving at the same speed. Maintaining position in the water column by small jumps was more costly for EC females, requiring 2.2–2.3 times more jumps and energy. Consequently, the persistence of EC females was limited in the open water. In M. leuckarti and M. albidus, the average speed and distances of jumps were 5–6 and 1.5–2.2 times higher, respectively, and the duration of jumps was 2.2–2.5 times shorter during escape than routine swimming. The maximum jumping speeds of NEC females, 40.6 and 50.5 cm s−1, respectively, were 12–14% higher than those of EC females, whereas their power and cost of transport were 16 and 23% lower, respectively. These results clearly indicated that egg sacs impair swimming and increase energetic costs of movement.

Application Effect of Bacillus in Tomato Root Knot Nematode Disease Control

Root-knot nematode is a kind of omnivorous plant pathogenic nematode that causes great harm to underground roots and above-ground parts of plants, and has become a serious factor restricting the development of global agriculture. In order to realize the sustainable development of agriculture, the research carried out an in-depth discussion on biological control methods. Firstly, a bacillus was obtained through insecticidal experiments, then a large amount of materials was obtained through purification and cultivation, and then the stability test of the active substance of Bacillus was conducted to explore its influence to root-knot nematodes. Finally, the pot verification experiment and field verification experiment were conducted. The results showed that in the insecticidal experiment, the accumulation of active substances at 14 h was the maximum, and the corresponding mortality of root-knot nematodes at 12 h and 24 h was 97.6% and 82.91%, respectively. In the BS pot experiment, the number of tomato root knot formation in the bacillus treated group was significantly reduced by 46.3% compared with the control group, and the number of egg sac of the rhizome was reduced by 78.31%. On the 120th day of field verification experiment, the fruit quantity and yield per plant in the treatment group increased by 17.02% and 11.85%, respectively. In summary, Bacillus can effectively reduce the damage of root knot nematode to tomato plants, and has a good prospect of application and popularization.

Escape performance in the cyclopoid copepod Oithona davisae

Escaping a predator is one of the keys to success for any living creature. The performance of adults (males, females, and ovigerous females) of the cyclopoid copepod Oithona davisae exposed to an electrical stimulus is analysed as a function of temperature by measuring characteristic parameters associated with the escape movement (distance covered, duration of the appendage movement, mean and maximum escape speeds, Reynolds number). In addition, as a proxy for the efficiency of the motion, the Strouhal number was calculated. The escape performance showed temperature-dependent relationships within each adult state, as well as differences between sexes; additionally, changes owing to the presence of the egg sac were recorded in females. In a broader perspective, the results collected reveal the occurrence of different behavioural adaptations in males and females, adding to the comprehension of the mechanisms by which O. davisae interacts with its environment and shedding new light on the in situ population dynamics of this species.

Revising Spider Egg-predating Fly Records (Diptera: Sarcophagidae): New Insights on Prey, Taxonomy, and Distribution of Sarcophaga (Mehria) lorosa Hall in Southern South America.

Flesh flies (Diptera: Sarcophagidae) exhibit a wide range of feeding habits including necrophagy, coprophagy, kleptoparasitism, parasitism, and predation. Among them are species of Sarcophaga Meigen belonging to the subgenera Baranovisca Lopes and Mehria Enderlein that are specialized predators of spider eggs. These flies hover around spider webs and lay their larvae on the spider egg sac. While progress has been made on the taxonomy of Baranovisca and Mehria in recent decades, our knowledge about their biology, prey selection, and distribution remains limited, restricting our understanding of the evolutionary dynamics of Sarcophagidae-Araneae interactions. Here, we describe and illustrate the first record of S. (M.) lorosa Hall preying on egg sacs of Metepeira galatheae (Thorell) (Araneae: Araneidae) in Chile. The taxonomy of S. (M.) lorosa is revised, with two new junior synonyms proposed: Weyrauchimyia ruficauda Lopes and Tibana, syn. nov., and Arachnidomyia travassosi Tibana and Mello, syn. nov. Furthermore, we present an annotated catalog that comprehensively reviews the existing records of spider egg-predating Sarcophagidae, and provide an overview of the evolution of Sarcophagidae-Araneae interactions. Our catalog includes information on at least four species of Baranovisca and 10 species of Mehria that have been documented as preying on eggs from species of various spider families, such as Araneidae, Cheiracanthiidae, Clubionidae, Philodromidae, Salticidae, and Tetragnathidae. These records cover all biogeographical regions except the Afrotropical. Our results enhance our understanding of the evolution of Sarcophagidae-Araneae interactions.

New mycoparasitic species in the genera Niveomyces and Pseudoniveomycesgen. nov. (Hypocreales: Cordycipitaceae), with sporothrix-like asexual morphs, from Thailand.

Four new species of the genus Niveomyces are described from Thailand. They were found as mycoparasites on: Ophiocordyceps infecting flies (Diptera) for Niveomyces albus; ants (Hymenoptera) for N. formicidarum; and leafhoppers (Hemiptera) for N. hirsutellae and N. multisynnematus. A new genus, Pseudoniveomyces with two species: Pseudoniveo. blattae (type species), parasitic on Ophiocordyceps infecting cockroaches, and Pseudoniveo. arachnovorum, found on a spider egg sac, are also described. These fungi share a common feature which is a sporothrix-like asexual morph. Based on our molecular data, Sporothrix insectorum is shown to be affiliated to the genus Niveomyces, and thus a new combination N. insectorum comb. nov. is proposed. Niveomyces coronatus, N. formicidarum and N. insectorum formed the N. coronatus species complex found on ant-pathogenic Ophiocordyceps from different continents. Pseudoniveomyces species are distinguished from Niveomyces spp. based on the presence of fusoid macroconidia in culture and a red pigment diffused in the medium, resembling to Gibellula and Hevansia. The molecular phylogenetic analyses also confirmed its generic status. The host/substrates associated with the genera within Cordycipitaceae were mapped onto the phylogeny to demonstrate that mycoparasitism also evolved independently multiple times in this family. Citation: Kobmoo N, Tasanathai K, Araújo JPM, Noisripoom W, Thanakitpipattana D, Mongkolsamrit S, Himaman W, Houbraken J, Luangsa-ard JJ (2023). New mycoparasitic species in the genera Niveomyces and Pseudoniveomyces gen. nov. (Hypocreales: Cordycipitaceae), with sporothrix-like asexual morphs, from Thailand. Fungal Systematics and Evolution 12: 91-110. doi: 10.3114/fuse.2023.12.07.

New Data on Spawning Site and Group Egg Laying of &lt;i&gt;Onychodactylus fischeri&lt;/i&gt; (Boulenger, 1886) (the Southern Sikhote-Alin Range, Russia)

At the end of May, a permanent spawning site of Onychodactylus fischeri was first discovered in the gravel-stony layer under the bottom of a small river valley in the upward flows of subsurface alluvial waters (upper reaches of the Pravaya Sokolovka River, the Sikhote-Alin Range, Chuguevka rayon, Primorsky Krai). This place was located at an altitude of 650 m a.s.l. in mixed coniferous-broad-leaved forest in a narrow river valley. The primary spawning site lay beneath the bottom of a small water body that was two meters away from the main river course. The water in the breeding ground was slightly acidic and slightly mineralized. The local population of O. fischeri begins to reproduce in the end of May, when the water temperature inside the site reaches 6.1 – 7.9°C. This site had been used for egg laying on multiple occasions. We found 72 clutches attached to several small stones (n = 11). There were no large cavities between the stones, only narrow gaps. There were two recently laid clutches, 26 clutches in the late stages of embryogenesis, already empty sacs and fragments of old mucous stalks. O. fischeri lays paired egg sacs measuring 35.4 ± 1.9 mm (34.5 – 38.15; n = 3) in length. Egg arrangement in clutches of O. fischeri was varying: in one (or in two) rows in both sacs, or in one row — in one sac and in two — in the other. The mean number of eggs in each sac was 6.8 ± 1.3 (4 – 10; n = 55), the mean number of eggs in the clutch — 13.6 ± 2.2 (9 – 17; n = 27), the egg diameter — 8.08 ± 0.6 mm (6.71 – 8.9; n = 19). For the first time we recorded the otter (Lutra lutra) actively hunting adult O. fischeri. In late May – early July it preyed upon salamanders near the spawning site. The otter ate heads and bodies of O. fischeri but not tails. Perhaps, a high concentration of muciparous glands with poisonous secretion in the tails prevented the predator from eating them.

Which temperature matters? Effects of origin, rearing and test conditions on the chemical sensitivity of Pardosa amentata

AbstractSpiders may be adversely affected by pesticides, yet they are not included in regulatory risk assessment and a related standard guideline to test their sensitivity to chemicals is lacking. Different laboratory setups, including test temperature and relative humidity, have been shown to influence the sensitivity of spiders. The climate from which spiders originate and the rearing conditions in the laboratory prior to ecotoxicological testing may also alter their sensitivity to chemicals, potentially in interaction with test conditions. We investigated the influence of population origin, rearing and test temperature on the chemical sensitivity of the spider Pardosa amentata towards lambda‐cyhalothrin. We collected female P. amentata carrying egg sacs from two climates, i.e., boreal and cool temperate. Spiders were kept in the laboratory and their offspring were reared and tested at 15, 20 and 25°C. Hatching of egg sacs largely failed at 15°C, while a moderate spiderling mortality (40%) was recorded at 20°C. At 25°C, mortality increased (63%) and a faster developmental rate was observed. Rearing and test temperature had no significant effects on spider chemical sensitivity. However, spider chemical sensitivity differed between populations, with spiders from boreal climate being 38% more sensitive than spiders from cool temperate climate. A higher sensitivity towards lambda‐cyhalothrin increases the risk of population reduction in treated areas, with potential alterations of ecosystem functions such as biological control. Our results suggest that the climatic origin of test organisms deserves stronger attention in ecotoxicological research.

Andean giants: Priscula spiders from Ecuador, with notes on species groups and egg-sac troglomorphism (Araneae: Pholcidae)

The Andean genus Priscula Simon, 1893 includes the largest Neotropical pholcid spiders, but due to their mostly cryptic lifestyle they remain poorly collected and poorly studied. Many species available in collections remain undescribed and nothing has been published about the phylogeny and the biology of the genus. Here, we deal with a recent collection of Priscula spiders from Ecuador, the country of origin of the type species, P. gularis Simon, 1893. We describe eight new species, collected at 17 localities at altitudes from 640–3160 m, all based on males and females: P. azuay sp. nov., P. llaviucu sp. nov., P. espejoi sp. nov., P. esmeraldas sp. nov., P. chapintza sp. nov., P. pastaza sp. nov., P. bonita sp. nov., and P. lumbaqui sp. nov. We use a sample of approximately 26 species-level taxa, mostly from Ecuador and Venezuela, to propose a first hypothesis about relationships within the genus. Our data (mainly CO1) suggest the existence of five species groups, three of which are represented in Ecuador. The cave-dwelling P. pastaza sp. nov. is only slightly troglomorphic (paler than usual; anterior median eyes strongly reduced or lost) but differs dramatically from forest-dwelling congeners in its biology: it hangs fully exposed in its web during the day; it produces egg sacs with only 6–7 eggs (average in 15 other species: 42 eggs); and it produces the largest eggs relative to body size of all studied species.

Aeromonas salmonicida, causative agent of salmonid furunculosis, isolated from the freshwater parasitic copepod, Salmincola californiensis.

Here, we provide evidence that the freshwater parasitic copepod, Salmincola californiensis, acts as a vector for Aeromonas salmonicida. While investigating the effects of S. californiensis on Chinoook salmon (Oncorhynchus tshawytscha), we tangentially observed that fish infected with the copepod developed furunculosis, caused by A. salmonicida. This occurred despite being reared in pathogen-free well water in a research facility with no prior history of spontaneous infection. We further investigated the possibility of S. californiensis to serve as a vector for the bacterium via detection of fluorescently labelled A. salmonicida inside the egg sacs from copepods in which the fish hosts were experimentally infected with GFP-A449 A. salmonicida. We then evaluated copepod egg sacs that were collected from adult Chinook salmon from a freshwater hatchery with A. salmonicida infections confirmed by either culture or PCR. The bacterium was cultured on tryptic soy agar plates from 75% of the egg sacs, and 61% were positive by PCR. These three separate experiments indicate an alternative tactic of transmission in addition to direct transmission of A. salmonicida in captivity. The copepod may play an important role in transmission of the bacterium when fish are more dispersed, such as in the wild.

A new species of Cardiodectes Wilson C.B., 1917 (Copepoda: Siphonostomatoida: Pennellidae) from Spinyjaw greeneye, Chlorophthalmus corniger Alcock, 1894 off the Indian Ocean.

A new species of flesh penetrating parasitic copepod of the genus CardiodectesWilson C.B., 1917 (Siphonostomatoida: Pennellidae) parasitizing the fish Spinyjaw greeneye, Chlorophthalmus cornigerAlcock, 1894 (Chlorophthalmidae), inhabiting at depths of 265 to 458 meters from the south-west coast of India is described and illustrated. The new species, Cardiodectes vampire sp. nov., can be distinguished from its other 16 congeners by the following features: (i) trunk 3.15 times as long as wide; (ii) extremely long (3.5 times as long as total body length) and uncoiled egg sacs; (iii) difference in the armature of legs 13; (iv) comparatively longer trunk (0.7 times as long as total body length). A checklist of valid global species of Cardiodecteswith its host and distribution is also provided.

Land planarians (Platyhelminthes) also prey on web-building spiders

Although spiders and land planarians constitute diverse groups of terrestrial predators, interactions between them are still unknown. Here, we describe a predatory event of a land planarian (Choeradoplana cf. gladismariae) on a web-building spider (Helvibis longicauda) in the Brazilian Atlantic Forest. The prey was constricted and covered with sticky mucus while remaining on its web trying to protect its egg sac. The event was observed in the middle-end afternoon at ca. 1.80 m height. Our observation broadens the scope of possible natural enemies of web-building spiders and the prey items of land planarians. It also indicates that these organisms can capture and overpower dangerous predatory arthropods, suggesting that even complex three-dimensional sticky webs can be ineffective against the attack of land planarians. Finally, we also show that land planarians can exhibit a flexible foraging strategy, exploiting the environment during the day and at higher heights from the ground. Our observation opens new possibilities involving focal observations and experiments using spiders and land planarians as models in predator-prey research.

Spatial Variation in Egg Sac Transparency of the Japanese Black Salamander, Hynobius nigrescens, Related to Environmental Gradients in the Ryohaku Mountains, Ishikawa Prefecture

Spatial Variation in Egg Sac Transparency of the Japanese Black Salamander, Hynobius nigrescens, Related to Environmental Gradients in the Ryohaku Mountains, Ishikawa Prefecture