Dramatic Dietary Shift Maintains Sequestered Toxins in Chemically Defended Snakes

Unlike other snakes, most species of Rhabdophis possess glands in their dorsal skin, sometimes limited to the neck, known as nucho-dorsal and nuchal glands, respectively. Those glands contain powerful cardiotonic steroids known as bufadienolides, which can be deployed as a defense against predators. Bufadienolides otherwise occur only in toads (Bufonidae) and some fireflies (Lampyrinae), which are known or believed to synthesize the toxins. The ancestral diet of Rhabdophis consists of anuran amphibians, and we have shown previously that the bufadienolide toxins of frog-eating species are sequestered from toads consumed as prey. However, one derived clade, the Rhabdophis nuchalis Group, has shifted its primary diet from frogs to earthworms. Here we confirm that the worm-eating snakes possess bufadienolides in their nucho-dorsal glands, although the worms themselves lack such toxins. In addition, we show that the bufadienolides of R. nuchalis Group species are obtained primarily from fireflies. Although few snakes feed on insects, we document through feeding experiments, chemosensory preference tests, and gut contents that lampyrine firefly larvae are regularly consumed by these snakes. Furthermore, members of the R. nuchalis Group contain compounds that resemble the distinctive bufadienolides of fireflies, but not those of toads, in stereochemistry, glycosylation, acetylation, and molecular weight. Thus, the evolutionary shift in primary prey among members of the R. nuchalis Group has been accompanied by a dramatic shift in the source of the species’ sequestered defensive toxins

Description of the final-instarlarva and pupa of Acanthacorydalis orientalis (McLachlan, 1899) (Megaloptera: Corydalidae) with some life history notes

Cao, Chengquan, Liu, Xingyue (2013): Description of the final-instarlarva and pupa of Acanthacorydalis orientalis (McLachlan, 1899) (Megaloptera: Corydalidae) with some life history notes. Zootaxa 3691 (1): 145-152, DOI: 10.11646/zootaxa.3691.1.

FIGURE 2 in Description of the final-instarlarva and pupa of Acanthacorydalis orientalis (McLachlan, 1899) (Megaloptera: Corydalidae) with some life history notes

FIGURE 2. Last-instar larva of Acanthacorydalis orientalis (McLachlan). A, Dorsal view; B, Ventral view; C, The 3rd to 5th segment of antennae, photographed by SEM; D, Hair brush on abdominal segment 9, photographed by SEM. Scale bar = 5.0 mm.Published as part of <i>Cao, Chengquan & Liu, Xingyue, 2013, Description of the final-instarlarva and pupa of Acanthacorydalis orientalis (McLachlan, 1899) (Megaloptera: Corydalidae) with some life history notes, pp. 145-152 in Zootaxa 3691 (1)</i> on page 148, DOI: 10.11646/zootaxa.3691.1.5, <a href="http://zenodo.org/record/10098830">http://zenodo.org/record/10098830</a&gt

FIGURE 1 in Description of the final-instarlarva and pupa of Acanthacorydalis orientalis (McLachlan, 1899) (Megaloptera: Corydalidae) with some life history notes

FIGURE 1. Collecting sites for Acanthacorydalis orientalis (McLachlan). A. Map of the collecting sites, asterisk represents Leshan City, black circle represents Panzhihua City; B. Qingying River, Jiajiang County, Leshan City; C. Anning River, Miyi County, Panzhihua City, China.Published as part of <i>Cao, Chengquan & Liu, Xingyue, 2013, Description of the final-instarlarva and pupa of Acanthacorydalis orientalis (McLachlan, 1899) (Megaloptera: Corydalidae) with some life history notes, pp. 145-152 in Zootaxa 3691 (1)</i> on page 146, DOI: 10.11646/zootaxa.3691.1.5, <a href="http://zenodo.org/record/10098830">http://zenodo.org/record/10098830</a&gt

FIGURE 3 in Description of the final-instarlarva and pupa of Acanthacorydalis orientalis (McLachlan, 1899) (Megaloptera: Corydalidae) with some life history notes

FIGURE 3. Pupa of Acanthacorydalis orientalis (McLachlan). A, Male pupa, lateral view; B, Female pupa, lateral view; C, Male pupa, dorsal (left) and ventral (right) view; D, Female pupa, dorsal (left) and ventral (right) view. Scale bar = 5.0 mm.Published as part of <i>Cao, Chengquan & Liu, Xingyue, 2013, Description of the final-instarlarva and pupa of Acanthacorydalis orientalis (McLachlan, 1899) (Megaloptera: Corydalidae) with some life history notes, pp. 145-152 in Zootaxa 3691 (1)</i> on page 150, DOI: 10.11646/zootaxa.3691.1.5, <a href="http://zenodo.org/record/10098830">http://zenodo.org/record/10098830</a&gt

Two new species of the genus Xya Latreille, 1809 (Orthoptera, Tridactyloidea, Tridactylidae) from Yunnan with a key to all Xya species in China

This contribution to the taxonomy of Xya Latreille, 1809 (Orthoptera, Tridactyloidea, Tridactylidae) adds descriptions and photographic illustrations of two new species: Xya xishangbanna sp. nov. and Xya yunnanensis sp. nov. from Xishuangbanna, Yunnan Province, China. Xya xishangbanna sp. nov. can be diagnosed by the shiny dark brown hind femora, and the epiproct with a shallow bottom of the middle “v-shaped” crack in the upper part and straight sides; Xya yunnanensis sp. nov. can be diagnosed by the compound eye bearing no narrow band along the inner margin, and the epiproct with the bottom of the side edge with a sharply angled protrusion and a narrow lower anchor-shaped base less than 1/2 the width of the upper one. Distributional information and bionomics for these two new species and photos for the habitat are given. A key to all Chinese species of Xya is provided

Allometry and morphological trait relationship in the sexually dimorphic Chinese dobsonfly, Acanthacorydalis asiatica (Wood-Mason, 1884) (Megaloptera, Corydalidae)

Male insects with large weapons such as horns and elongate mandibles would be expected to invest more on such structures than other parts of the body for advantages in male to male competition for mating. In male genitalia, however, intermediate size provides a better fit for more females than small or large sizes, and such a male would leave more offspring regardless of their body size. These predictions were tested using a static allometry analysis between body size and other trait sizes. Acanthacorydalis asiatica is a large dobsonfly (Megalotera) and males have conspicuously large mandibles used as weapons. We examined the hypothesis that the male mandibles of this sexually dimorphic species are sexually selected to enlarge, whereas the male genitalia are stable to be intermediate regardless of a great variation in body size. The results, as predicted, showed positive allometry between male body size and mandible length but negative allometry between male body size and ectoproct length (a male grasping structure). Sperm are transferred through a small spermatophore attached externally to the female genital opening, so it may be evolutionarily unnecessary to develop an enlarged male genital size. In contrast, there may be a trade-off between male mandible size and wing length, because of negative allometry between body size and wing length in males but isometry between them in females

FIGURE 1 in A new genus and a new species of pygmy mole cricket from mid-Cretaceous amber in North Myanmar (Orthoptera: Caelifera: Tridactyloidea)

FIGURE 1. Holotype (LNU-5) of Latedactylus longapedi sp. nov. holotype; (A) photograph of the habitus in the dorsal‐lateral view, (B) line drawing of the habitus, (C) photograph of the terminal abdomen in dorsal view, (D) line drawing of the terminal abdomen, (E) photograph of the right metatarsus, (F) line drawing of the right metatarsus. The abbreviations of the characters are as follows: protibia, pt; mesothoracic leg, meso; cercus, ce; paraproctal lobe, pptl; metatarsus, mt; apical spur, asp; subapical spur, sasp.Published as part of <i>Zheng, Chengjie, Cao, Chengquan & Gu, Jun-Jie, 2023, A new genus and a new species of pygmy mole cricket from mid-Cretaceous amber in North Myanmar (Orthoptera: Caelifera: Tridactyloidea), pp. 296-300 in Zootaxa 5339 (3)</i> on page 298, DOI: 10.11646/zootaxa.5339.3.7, <a href="http://zenodo.org/record/8309090">http://zenodo.org/record/8309090</a&gt

A new genus and a new species of pygmy mole cricket from mid-Cretaceous amber in North Myanmar (Orthoptera: Caelifera: Tridactyloidea)

Zheng, Chengjie, Cao, Chengquan, Gu, Jun-Jie (2023): A new genus and a new species of pygmy mole cricket from mid-Cretaceous amber in North Myanmar (Orthoptera: Caelifera: Tridactyloidea). Zootaxa 5339 (3): 296-300, DOI: 10.11646/zootaxa.5339.3.7, URL: http://dx.doi.org/10.11646/zootaxa.5339.3.

Adults of Alderflies, Fishflies, and Dobsonflies (Megaloptera) Expel Meconial Fluid When Disturbed

Chemical secretions are an effective means by which insects may deter potential enemies, already being studied extensively with regard to their chemicals, synthesis, toxicity, and functions. However, these defensive secretions have been little studied in Megaloptera. Herein, the fluid expelling behavior of adult alderflies (Sialidae), fishflies (Corydalidae: Chauliodinae), and dobsonflies (Corydalidae: Corydalinae), all of the order Megaloptera, is described in detail regarding the timing and possible function of this behavior. When disturbed artificially, both males and females could expel fluid from the anus. However, the frequency of expelling was much lower in alderflies than in fishflies and dobsonflies. The amount of expelled fluid relative to body weight was also smaller in alderflies. In fishflies and dobsonflies, the amount of expelled fluid decreased with adult age, probably because the fluid is little replenished once expelled. The cream-colored fluid seems to be meconial fluid produced via the Malpighian tubules at the pupal stage, which is usually discharged at adult emergence in most other holometabolous insects. However, adult fishflies and dobsonflies often expel it vigorously by bending their abdomen when disturbed after emergence. Thus, the fluid expelling may be an anti-predatory behavior, particularly in younger adults that can expel a relatively large amount of fluid