#ground beetles

Abstract

A pioneer study of ground beetles and tiger beetles was conducted in the protected forest of Lake Danao, Leyte, Philippines. A total of 1647 ground and tiger beetle individuals belonging to 26 species were collected. A total of 19 endemic species were recorded of which 12 are Philippine endemic while six (6) and one (1) are endemic to Leyte and Samar, respectively. This result serves as a baseline data of ground and tiger beetles in the forest of Lake Danao. The most dominant tribe recorded is Brachinini under Subfamily Carabinae with 8 species and followed by Cecindelini with 6 species. Tribe Collyridini consists of 5 species while both Lebiini and Chlaeniini have four species each. Most tribes garnered two and one species respectively. New additions in Leyte are Brachinus leytensis, Trigonotoma goeltenbothi, Pheropsophus lumawigi, Pheropsophus azoulayi, Pheropsophus uliweberi, and Pheropsophus sp. The last three species were discovered and identified in this study. Ecological notes were also presented for the species as well as their distribution and occurrence. Conservation should be conducted to the carabid beetles especially the rare and endemic ones in some forests. Strengthened implementation of protection in both protected landscapes against mining, illegal logging, slash and burn farming and human settlements should also be done.

Introduction

Tropical forests as the most varied and the most biologically complex ecosystem provide apparently over 33% all species considered (Raven 1980; Wilson 1992) and assume an excessively vast part in worldwide carbon and other nutrient cycles (Detwiler & Hall 1988). In view of its high heterogeneity, i.e. more prominent assortment of microhabitats, a wider scope of microclimates and expanded resource range could happen. It can likewise offer a rich diversity of invertebrates and vertebrates (Huston 1993; Townsend et al., 2008). Most studies on biodiversity loss have focused on mammals (Dirzo & Raven 2003; Gonzalez 2013), birds (Gregory et al., 2005; de Lima et al., 2013; Boyer & Jetz 2014) and plants (Wood et al., 2013; Newbold et al., 2014). However, the decline and extinction rates of insects, which comprise the majority of terrestrial biodiversity, are inadequately quantified and poorly understood in different parts of the world (Dunn 2005; Thomas 2005; Runge et al., 2014).

Of all the insect orders, Order Coleoptera dominates and constitutes 40% of the total number. The family Carabidae, comprises of ground beetles and tiger beetles, is composed of approximately 40,000 known species and are arranged into 86 tribes (Erwin 1985). It is the biggest adephagan family and a standout amongst the beetle families. The suborder Adephaga is a comparatively large group of beetle that is morphologically described by having of six abdominal ventrites, pygidial defense glands in adult, and fluidfeeding mouthparts in the larvae stage (Lawrence and Britton 1991). They are proportional cursorial beetles with noticeable mandibles and palps, long thin legs, striate elytra, and sets of punctures with tactile setae. They commonly contain an antenna-cleaning organ and big pubescent reception antennae. The mature carabids generally dark colored, sparkly or matte. Others have brilliant or metallic hues, and some are pubescent. The larvae are campodeiform, have all around developed legs, antennae, and mandibles, and bear settled urogomphi (Crowson 1981). Several authors grouped carabids into various subfamilies; with the exception of the tiger beetles (Pearson 1988), where environmental information is still inadequate concerning subfamilies outside the Carabinae (Lawrence and Britton 1991). The abundance, richness, and alluring color of numerous species have made carabids well known objects of study for both expert and beginner entomologists. Carabids can be seen around the world, with species richness recorded highest in the tropical areas. They live in about in every accessible environment, though few species are associated with specific habitats, i.e. meadows, forests, or harvest fields. Because of habitat specificity of few species, carabids can be utilized as biological indicators to evaluate land use changes in various biological communities (Erwin 1985).

Carabid beetle fauna (ground and tiger beetles) is a standout amongst the exceptional organisms on the planet in spite of its small geographical area. Philippines positions fifth as far as its lavishness and third on the level of endemism after Madagascar and Australia (Cassola and Pearson 2000; Cassola and Ward 2004; Cassola 2011). Philippines lands number one as far as endemism per unit area. Yet, little consideration has been given to the nation's carabid fauna, to their conservation status, and the presumable impact of environmental changes and human activities on these groups. Initial collections started way back 1859 - 1865 by C.G. Semper and 1913-1919 by G. Boettcher. These carabid beetles were introduced by European entomologist, Schaum (1860, 1862, 1863) and Horn (1907, 1908, 1909, 1923, 1924, 1937). Latest publication and review on the carabid fauna of the Philippines were conducted by Ceniza (1994), Cassola (2000, 2011), Cassola and Ward (2004), Cassola and Zettel (2006), Deuve (2015), Dheurle (2015), Naviaux (1992, 2002), Wiesner (1980, 1988a, 1988b, 1989, 1992a, 1992b, 2015). The identification of new species Thopeutica milanae by Weisner in 1992 in Leyte, marked the beginning of carabid study in Eastern Visayas, and is continuously being given an attention because of its promising endemic species. Additional four carabid species were identified from Leyte in succeeding years namely: Elaphropus schawalleri, E. surrulipennis, E. martensi and Paratachys leytensis Baehr (2016). Still, new species of carabids from Leyte and Cebu were identified by Lassalle & Schnell (2018) namely: Brachinus bendanilloi and Pheropsophus (Stenaptinus) azoulayi. Similar recommendations were given in these studies, and that is to continue collecting for the discovery of new species and conduct collections in other forests of Eastern Visayas.

The study aims to document the different species of carabid and tiger beetles found in the forest of Lake Danao, Leyte, Philippines. Specifically, it aims to collect samples, describe, classify and catalogue the different species found.

Amara aenea is one of the shiny beetles you can spot in North America and Eurasia. It belongs to the Carabidae family known as ground beetles – one of the largest insect families comprising over 40,000 species. Ground beetles vary in color and shape, but most are shiny black or metallic with ridges on their wing covers. Many are completely flightless because of their elytra being fused together. They have broad feeding habits but are generally carnivorous and predatory, which is made possible by their strong mandibles.

Such is also the case with Amara aenea! They eat smaller insects considered pests.

They like to run around on sunny days, which is where their common name comes from! Always makes me happy to see them:)

PS. his name is Vergil (requested by a friend who saw me drawing)