Saturday, 15 August 2015

Eneopterine Crickets from Leyte Island.

Leyte is the eighth largest island in the Philippines and is considered a site of high biodiversity and conservational importance, particularly the forested mountainous interior of the island. The island was formed by volcanic activity along the Philippine Trench (a subductive plate margin, where one tectonic plate is being forced below another and melted by the heat of the Earth’s interior, with some of the resultant magma rising through the overlying plate to form volcanoes), during the Pleistocene, when it was attached to Greater Mindanao Island. As such it has rich volcanic soils and a fauna and flora made up entirely of species that have colonized during or since the Pleistocene or evolved in situ since this time. Leyte has a tropical climate wet all year round, with the southern part of the island having a distinctive period of higher rainfall between November and April. Despite being an area of acknowledged biogeographical and conservational importance, much of the interior of Leyte remains unexplored by biologists.

In a paper published in the Raffles Bulletin of Zoology on 14 April 2015, Tony Robillard of the Muséum national d’Histoire naturelle in Paris and Sheryl Yap of the College of Agriculture and Museum of Natural History at the University of the Philippines Los Baños, describe two new species of Eneopterine Crickets as part of a study of this group on Leyte Island. Eneopterines are small Crickets with distinctive mating signals, noted for their high diversity on the islands of the Pacific and the Philippines in particular.

The first new species described is placed in the genus Lebinthus, which is known from the Philippines, Indonesia and Singapore, and given the specific name estrellae, in honour of Regene ‘Estrella’ Portillo, who helped with accessing the locality where the species was discovered and with collecting specimens. The species is described from three male, sixteen female and four juvenile specimens collected in secondary rain forest on a slope at Barangay Villa Corazon near Burauen in the interior of Leyte Island, as well as one male captured as a juvenile at the same location and raised in captivity.

Lebinthus estrellae: (A) Female and (B) juvenile specimens in leaf litter secondary forest, Barangay Villa Corazon. Robillard & Yap (2015).

Lebinthus estrellae is smaller than other members of the genus, and dark brown in colour with white and yellow markings and a lighter orangish or pinkish brown band on each eye. It was found living in small bushes and leaf litter in secondary rain forest. The males produced a short trilling song with 83-91 sylables.

The second new species described is placed in the wingless genus Paranisitra, which is known from the Philippines and offshore islands of New Guinea, and given the specific name leytensis, meaning ‘from Leyte’. The species is described from two male, six female and four juvenile specimens collected from secondary rainforest at Barangay Villa Corazon and Buo near Burauen in the interior of Leyte Island.

Paranisitra leytensis, new species: (A) Female and (B) male specimens in natural habitat near Burauen, Leyte. Regene Portillo in Robillard & Yap (2015).

Paranisitra leytensis is considerably smaller than other members of the genus, with the males being notably smaller than the females. The adults are yellow- or grey-brown, with black and white markings, these differing between the sexes. Juveniles are colourful, with green red and yellow patterns, later instars developing the adult colouration.

Paranisitra leytensis, juvenile specimen in dorsal view. Scale bar is 1 mm. Robillard & Yap (2015).

See also…

Mud Crickets, Ripipterygidae, are small Orthopterans...

Katydids (or Buschcrickets), Tettigonioidea, are Members of the Insect Order Orthoptera, which also includes Crickets and Grasshoppers. They are voracious eaters and can consume a...

Katydids of the genus Xizicusand its close relatives are found across eastern Asia, though the taxonomy of the group is currently somewhat confused, in part due to publications being published in different languages...

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