Arthropod Biodiversity Exploration in Hainan Island – Possibly 4 or 5 Species of Un-Described Spider Species Found

by
A.T. Barrion,  S. Villareal, International Rice Research Institute, Los Baños, Philippines and
Cai Du Cheng, Hainan University, Danzhou, PR China

Participants of the training on arthropod biodiversity, taxonomy and identification in Danzhou campus, Hainan

Hainan rice fields provide a tropically-scenic agricultural landscape in the pear-shaped island noted for beautiful beaches. Rice is grown from intensive monoculture to diverse agricultural corridors of terrestrial and aquatic habitats rich in biodiversity and ecosystem services. In these environments, ecosystem services, such as resistance to pest invasion and pest regulation provided by the beneficial species—predatory insects, spiders and mites; parasitoids; parasites; and pathogens are important factors that keep pest populations below economic thresholds. It has been estimated that the ephemeral rice habitats in Hainan may have around 200 species of parasitoids and 150 species of predators having refuge in and around rice fields after rice is harvested and re-entering the rice fields upon establishment of the crop. This wide pool of natural enemies dominated by resident generalist predators like spiders and crickets would regulate the exogenous migrant pest species. The surrounding landscape structure, habitat biodiversity, cropping patterns, and the farmers’ crop management practices are important for these species and their functions. High pesticide use may cause breakdown of ecosystem services, which will lead to uncontrollable outbreaks of pest species. Changing the practice by reducing pesticide use and strengthening ecosystem services is the only way to reverse the situation.

Today, nearly 100% of rice grown in Hainan Island is hybrid rice. Farmers are also encouraged to apply insecticides routinely 3 to 4 times per season. Rice monoculture promoting low genetic biodiversity coupled with high pesticide applications that kill the population of beneficial and resident natural enemies of pests make farms adamantly vulnerable to pest outbreaks. Farmers are also unaware of biodiversity and the natural biological control services in their farms, and their routine spraying practices trigger loss or death of services. Government officials, university professors, researchers and farmers are traditional and rely solely on pesticides for pest control. To avoid potential risks of pest outbreaks, all these workers have to be taught making rice production environmentally sustainable, how to conserve and preserve local biodiversity, and “do-away” with pesticides to strengthen natural biological services. Abandoning pesticide use forms a positive gain in ecosystems services and   enhances pollination services in the agricultural landscapes of fruit, flower, vegetable and plantation crops.  Apiculture industry is likely to flourish in Hainan upon adoption of no spray policy.

biodiversity exploration using a suction sampling device

The project entitled “Conserving Arthropod Biodiversity and Ecosystem Services in Rice Environments of Hainan Island” aims to foster collaboration with local Hainanese scientists in the island to assess arthropod biodiversity and ecosystem services in rice environments, to understand farmers’ knowledge, attitude and practices with regards to biodiversity conservation and to develop strategies for conservation.  Training local partners in arthropod taxonomy, identification and different collecting techniques for the endemic and invasive arthropod fauna occurring in rice environments is of paramount value. Thus, a training course on arthropod biodiversity exploration, taxonomy, identification and sampling techniques was conducted on August 2 to 13, 2010 in Danzhou Campus, Hainan University, Hainan Island. Sampling technique basic to exploration was the first major activity taught to the trainees. The training course on the different sampling techniques was conducted on August 2- to 7, 2010 and taught the students the different methods of samplings in rice environments. The sampling techniques used range from sweep net, malaise trap, pitfall trap, yellow pan, hand picking and vial tapping and suction machine.

A Malaise trap to capture flying arthropods

Initial estimates of the arthropod biodiversity exploration made in four sites, namely, Haikou, Lingshui, Sanya and Danzhou yielded some 5,000-8000 individuals representing 168 species of insects belonging to 88 families and 13 orders; spiders—27 species in 12 families; mites – 4 species in 3 families; crustaceans—2 species in 2 families; and a huge annelid—1 species in a single family. Identification to the species level is underway. It is noteworthy to mention that about 4 to 5 undescribed species spiders belonging to the families of Tetragnathidae, Zodariidae, Linyphiidae and Salticidae were collected in Hainan. Research is in progress to determine their taxonomy.

A 5-day arthropod training course on taxonomy and identification followed the biodiversity exploration run for the first time in Danzhou campus, Hainan University, Hainan Island on August 9-13, 2010. The training course set three objectives and focused primarily on preparing participants to acquire (1) skills to identify the differences between arthropod orders and families; (2) skills to identify the major diagnostic features of the most common and important arthropod orders, families and species especially insects and spiders in the rice agricultural landscape using taxonomic keys; and (3) skills to handle and preserve arthropods for identification.

Eighteen participants—8 students and 10 government workers joined the training program. Of these, only 16 participants successfully completed the taxonomy and identification course. The participants were provided a lecture series on distinguishing different arthropods like insects and spiders; on proper collection, sorting and preserving arthropods; and on how to use taxonomic and picture keys. Trainees were taught hands-on preservation and labeling collections, mounting on paper card points and glass slides, and preservation of larvae without losing much the natural body color.

The taxonomy course dealt with 10 insect orders—Odonata, Orthoptera, Dermaptera, Thysanoptera, Hemiptera, Coleoptera, Strepsiptera, Lepidoptera, Diptera and Hymenoptera, and Araneae with representatives of at least 102 families of arthropods (91 insects and 11 spiders).

In the training course was a successful one based on percentage post evaluation results and the higher taxonomic knowledge gain (TKG). Overall, the participants enjoyed the taxonomy training course on-the-road and learned the skills in the processing and preservation of arthropods, and developed the skills in identifying the different orders and families of insects and spiders of Hainan Island.

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