Skip to main content

Taiwanese ambrosia beetle (Eccoptopterus formosanus) and midst ambrosia beetle (Eccoptopterus intermedius)

Taiwanese ambrosia beetle (Eccoptopterus formosanus) and midst ambrosia beetle (Eccoptopterus intermedius)

NEWS - Two xyleborine ambrosia beetles, Taiwanese ambrosia beetle (Eccoptopterus formosanus Lin, Sittichaya & Smith, sp. nov.) and midst ambrosia beetle (Eccoptopterus intermedius Sittichaya, Lin & Smith, sp. nov.) described from Taiwan and Thailand based on DNA sequences (COI and CAD) and morphological characteristics.

Eccoptopterus Motschulsky 1863 is the earliest described xyleborine ambrosia beetle (Coleoptera: Curculionidae: Scolytinae). Victor Ivanovich Motschulsky assigned the name to the monotypic genus and a new species, E. sexspinosus Motschulsky 1863, described from Burma.

Currently 14 species and subspecies have been described of which 4 are: E. drescheri Eggers 1940, E. limbus Sampson 1911, E. spinosus (Olivier, 1800) and E. tarsalis Schedl 1936. Eccoptopterus is easily distinguished by its autapomorphically enlarged metatibiae and metatarsi.

Based on specimens collected as part of a survey of xyleborine ambrosia beetles in Thailand and Taiwan, researchers have found variations in Eccoptopterus specimens that suggest the potential for a new species.

E. formosanus female, 2.56−2.64 mm long (mean = 2.61 mm; N = 4), 2.13−2.17× as long as wide (mean = 2.14×; N = 4). Medium body size, declivital armature composed of a pair of major spines on declivital summit and 2–4 minor denticles unevenly spaced on each lateral margin; protibiae slender, broadest at apical 1/3, outer margin armed with six or seven moderated socketed denticles; scutellum broadly linguiform; elytra tapering laterally.

Bred from Elaeocarpus sylvestris (Lour.) Poir. (Elaeocarpaceae), Lithocarpus hancei (Benth.) Rehder, Quercus glauca Thunb. ex Murray (Fagaceae), Sapium discolor Muell.-Arg. (Euphorbiaceae), Trema orientale (L.) Blume (Cannabaceae) with a diameter of about 4.8–6.2 cm in Taiwan. The radial entrance gallery leads to several branches in various planes without enlarged brood chambers.

E. intermedius female, 1.70−1.90 mm long (mean = 1.80 mm; N = 6), 2.03−2.38× as long as wide (mean = 2.13×; N = 6). Small body size, declivital armature composed of a pair of major spines at interstriae 3 on declivital summit and four minor spines unevenly spaced on each lateral margin, declivity covered with flattened scale-like setae; protibiae slender, broadest at apical 1/3, outer margin armed with four or five moderated socketed denticles, elytra tapering laterally.

Formosa is the old name of the island of Taiwan, referring to the location of the type collection with a distribution in Nantou County). L. inter + medius = in the middle. The name refers to the morphological character of the species which is intermediate between E. limbus and E. spinosus. Distribution in Chiang Mai, Lamphun, Tak, Ubon Ratchathani provinces (Thailand).

The differences in COI and CAD sequences between the new species (E. formosanus, E. intermedius) and E. limbus, E. spinosus sensu lato and the junior synonym E. gracilipes are greater than the suggested species boundaries for these genera. Geographically separated morphological characters also show variation in the degree of elytral constriction and density of declivital setals.

E. intermedius is more similar to E. limbus than to E. spinosus but some characters are intermediate. E. intermedius differs from E. limbus by its smaller size, shorter elytra (elytra: pronotum), only four minor spines on the declivital margin, and more slender protibiae. It differs from E. spinosus by its hair-like declivital seta and only one pair of major spines and more slender protibiae.

E. formosanus is more similar to E. spinosus than to E. limbus. E. formosanus differs from E. spinosus in lacking the second and third major spines on the declivital margin and the declivital surface is densely covered with long, thick setae. It differs from E. limbus in having a smaller body size, tapering elytra and a declivital margin with 2–4 minor denticles.

Original research

Sittichaya W, Lin C-S, Smith SM, Pornsuriya C, Cognato AI (2024). Two new species of Eccoptopterus Motschulsky, 1863 ambrosia beetle from Taiwan and Thailand (Coleoptera, Curculionidae, Scolytinae, Xyleborini). ZooKeys 1217: 247-262, DOI:10.3897/zookeys.1217.129707

Dlium theDlium
Labels:

Popular Posts

Humpback whales (Megaptera novaeangliae) manufacture bubble-nets as tools to increase prey intake

NEWS - Humpback whales ( Megaptera novaeangliae ) create bubble net tools while foraging, consisting of internal tangential rings, and actively control the number of rings, their size, depth and horizontal spacing between the surrounding bubbles. These structural elements of the net increase prey intake sevenfold. Researchers have known that humpback whales create “bubble nets” for hunting, but the new report shows that the animals also manipulate them in a variety of ways to maximize catches. The behavior places humpbacks among the rare animals that make and use their own tools. “Many animals use tools to help them find food, but very few actually make or modify these tools themselves,” said Lars Bejder, director of the Marine Mammal Research Program (MMRP), University of Hawaii at Manoa. “Humpback whales in southeast Alaska create elaborate bubble nets to catch krill. They skillfully blow bubbles in patterns that form a web with internal rings. They actively control details such ...
Read more

Sweetpotato bug (Physomerus grossipes)

Kutu ketela or sweetpotato bug ( Physomerus grossipes ) is an insect species in Coreidae, brown with black legs, adults growing about 2 cm long, oval shaped, segmented antennas, heavily veined membranes, metathoracic odor glands and enlarged rear tibia. P. grossipes generally live in Leguminosae and Convolvulaceae especially sweet potato ( Physomerus grossipes ), pink morning glory ( Ipomoea carnea ), purple beans ( Vigna unguiculata ), Asian pigeonwings ( Clitoria ternatea ) and common bean ( Phaseolus vulgaris ). Sweetpotato bugs suck liquid from the stem which causes plants to wither and disrupt fruit production. P. grossipes places eggs at the bottom of the leaves or stems or grass around them. Females are very protective of their children, keeping eggs and nymphs from predators as the most famous example of maternal care in Coreidae. Even so, about 20% of eggs are eaten by predators such as ants and 13% are lost by parasitoid predation by chalcid wasps which lay eggs in egg...
Read more

Yellow potter wasp (Delta campaniforme)

Yellow potter wasp ( Delta campaniforme ) is a species of animal in Vespidae, solitary wasp, shiny yellow, shiny black, dull black and brown with a yellow striped belly, a long and narrow waist, a nest built using mud and a circle attached to a cliff. D. campaniforme has a black head with a yellow plot in the center and two transverse plots on the right and left. A pair of black eyes. A pair of antennas, long, yellow with a black base and tip. The back is yellow and black. A large black plot semicircle at the top of the front. The two plots form a circular line at the top of the back. A pair of wings is brownish black and transparent. The stomach has the shape of a water droplet, pointed tip, black with yellow and black segments, alternating to form stripes. Linear folds on the sides. The underside of the front is brown and large. The middle section has alternating yellow and black segments that form stripes. The stomach and back are connected by a long, narrow, downward curved pipe...
Read more