Tiger beetles (Coleoptera: Cicindelinae) of Davao Region, Mindanao, Philippines

An assessment of tiger beetles in select mountains of Davao region including Mt. Hamiguitan (MHRWS), Marilog District (MD), Davao City (DC), Sta. Cruz Davao del Sur (SCD), and Davao de Oro (DO) is herein presented. Materials were collected between December 2017 and February 2019 through a combination of opportunistic and standard light trapping methods. Twenty-two species belonging to 9 genera were recorded with 64% endemic in the Philippines. Nine (9) species are recorded from MHRWS, 6 from MD, 8 from DC, 5 SCD, and 14 from DO (formerly Compostela Valley Province). Tiger beetles showed consistent habitat preferences particularly riparian species which includes the genera Calomera, Thopeutica, Therates, Prothyma, Cylindera, and Heptodonta. Strictly arboreal species include Tricondyla, Therates, and Neocollyris. Strict epigeic species include but not limited to the genera Calomera, Tricondyla, Thopeutica, Cylindera, Heptodonta, Neocollyris, and Prothyma. Endemic species such as Heptodonta lumawigi (Wiesner, 1980), Thopeutica (Thopeutica) anichtchenkoi (Wiesner 2015), Thopeutica (Thopeutica) milanae (Wiesner, 1992), Thopeutica (Thopeutica) rolandmuelleri Cassola, 2000 and Thopeutica petertaylori (Medina, Cabras, Wiesner, 2019) prefers a more intact forests while others such as Cylindera (Ifasina) discreta elaphroides (Dokhtouroff 1882), Calomera mindanaoensis (Cassola, 2000) and Necollyris sp. could tolerate disturbed secondary forest even agricultural lands. New distribution record for Heptodonta lumawigi (Wiesner, 1980) and Thopeutica (Thopeutica) milanae (Wiesner, 1992) for Marilog District were also recorded. Ecological data and conservation status of tiger beetles are also presented. Conservation actions are deemed necessary in the remaining green spaces in Davao City that hosts tiger beetle fauna should also be conducted.


INTRODUCTION
The tiger beetles are predatory beetles recognized by their lengthy legs, prominent sickle mandibles, 11 segmented filiform antennae, and a pair of conspicuous large compound eyes (Pearson 1998). Their size ranges from 6mm to the extent of 45mm (Pearson 1998). Recent revisions of Lopez-Lopez & Vogler (2017) and a comprehensive molecular phylogeny of tiger beetles of Gough et al. (2018) placed the taxon into a separate family Cicindilidae. Among the insect taxa, tiger beetles are a bioindicators of biodiversity (Pearson & Cassola 1992) and information can be gathered by analyzing their habitat specificity, presence of endemic species, and a possible translation of patterns to related taxa (Nose 1990;Morgan et al. 2000).
The Philippines is home to a high number of unique species of Cicindilinae. In 1992, Wiesner recorded 94 species of Cicindelid in the Philippines. Between 1990 and 2000, Cassola & Pearson (2000)  Consequently, tiger beetle studies in the Philippines are still scant mostly focusing on taxonomy with very few faunistic data (Wiesner 1980(Wiesner , 1988a(Wiesner , 1988b(Wiesner , 1989(Wiesner , 1992a(Wiesner , 1992b(Wiesner , 2015Bogenberger 1988;Naviaux 1992Naviaux , 2002Cassola 2000Cassola , 2011Cassola & Ward 2004;Cassola & Zettel 2006;Deuve 2015;Dheurle 2015;Cabras et al. 2016 (Cabras et al. 2016). This paper presents the list of tiger beetles in Mt. Hamiguitan Range Wildlife Sanctuary Davao Oriental, Sta. Cruz Davao del Sur, green spaces of Davao City, and upland forests of Marilog District Davao City. Notes on their ecology and conservation status, which are an essential reference for conservation and monitoring purposes, are also presented. The daily collection was conducted using insect net and light trapping for nocturnal sampling from 18.00h to 22.00h. Collected specimens were killed using ethyl acetate and placed in 90% ethanol. Species identification was made by examining morphological characters were observed under Luxeo 4D and Nikon SMZ745T stereomicroscopes. Stacked digital habitus images were taken with Nikon D5300 digital camera and Sigma 18-250. All images were then stacked and processed using a licensed version of the software Photoshop CS6Portable with reference to taxonomic keys and published articles of Wiesner (1980Wiesner ( , 1988aWiesner ( , 1988bWiesner ( , 1989Wiesner ( , 1992aWiesner ( , 1992bWiesner ( , 2015, Cassola (2000Cassola ( , 2011, Cassola & Ward (2004), and Cabras et al. (2016).

RESULTS AND DISCUSSION
A total of 22 species belonging to nine genera were collected in all sampling sites (Table 1). Nine species were recorded from MHRWS, six from the mountain forests of Marilog District Davao City, eight from the urban green spaces of Davao City, five from Sta. Cruz Davao del Sur, and 14 species from Davao de Oro. Of the 22 species, nine (41%) are Philippine endemic, five (23%) are Mindanao endemic, four (18%) are distributed to Southeast Asia, and two (9%) are Oriental species. Five (23%) species are threatened according to the latest DENR Administrative Order (2017) https://www. philippineplants.org/dao-2017-11.pdf, while the other seventeen (77%) species are Data Deficient.
Most species of tiger beetles are matched to a specific environmental condition, which makes the diversity of the fauna strongly determined by the availability and variety of suitable habitats (Willis 1967;Knisley 1984). In general, tiger beetles preferred river edges, water beaches, dunes, sandy flats, woodland paths, grasslands, and areas with dirt roads, trails, sandpits, and spoil deposits (Knisley 2011). The difference in habitats including physical parameters such as soil characteristics, plant composition, and the presence of bare patches of the ground determine their composition since these species need bare spots of the field as a habitat requirement both for adults and larvae (Dreisig 1980). For adults, the presence of sunlight is an essential physical factor in maintaining their high body temperature to enhance speed and effectiveness in catching their prey. Majority of the tiger beetles captured during day time were collected in open spaces where sunlight can penetrate and near river edges and cliffs. Species like Heptodonta lumawigi (Wiesner, 1980), Thopeutica (Thopeutica) anichtchenkoi (Wiesner, 2015), Thopeutica (Thopeutica) milanae (Wiesner,  Cassola, 2000, and Thopeutica sp. are habitat-specific and prefer a more intact forest habitat. Few species like Cylindera (Ifasina) discreta elaphroides (Dokhtouroff, 1882) and Calomera mindanaoensis (Cassola, 2000), can thrive in relatively disturbed habitats. Both were collected in the University of Mindanao campus and remaining green spaces in Bago Gallera as well as a mixed agricultural farm in Matina Pangi Davao City, Philippines.
Species such as Heptodonta lumawigi (Wiesner, 1980), Thopeutica (Thopeutica) milanae (Wiesner, 1992), and Prothyma (Symplecthyma) heteromallicollis heteromallicollis (Horn, 1909) were observed on steeply sloping areas near creeks and rivers (Image 2B,C). Heptodonta lumawigi (Wiesner, 1980) seemed to favor sloping creeks but also collected along with the road cuts in open spaces (Image 2A). The high preference of this species to inhabit intact forest habitat might be one of the reasons why this species is recorded under threatened species. Heptodonta lumawigi (Wiesner, 1980) was first believed to be endemic to Panay when Wiesner recorded it in 1980. New specimens, however, were recorded by Cassola (2000) in Mt. Parker, South Cotabato, listing the species as widely spread in the Philippines. This is also the first time that H. lumawigi is recorded in the forest of Marilog District, Davao City. The species under the genus Therates, on the other hand, are commonly found near the rivers, usually in the leaves of shrubs and ferns. At times, two species of Therates can co-exist in the same riverine are such as Therates fulvipennis everetti (Bates, 1878) and Therates fasciatus fasciatus (Fabricius, 1801). All species of Therates share the same habitat type, shrubs in relatively disturbed secondary forests system, and shaded riverine sandy areas (Image 2D). The remaining green spaces of Davao City harbors eight species a testament of the importance of keeping the green spaces within urban areas for species to thrive and continue living. It is interesting to note that Cylindera (Ifasina) discreta elaphroides (Dokhtouroff, 1882) is documented both within the campus of the University of Mindanao Matina and in the secondary forests of Bago Gallera. Neocollyris sp. and Calomera mindanaoensis (Cassola, 2000) were captured in Shrine Hills, Matina, and in the agricultural ecosystem in Matina Pangi, respectively. Cassola & Ward (2004) observed different species of tiger beetles have various adaptations to the changing environment. Similar findings were observed by Cabras et al. (2016). The present list if more numerous compared to tiger beetle fauna in Calanasan Apayao Province which (Medina et al., 2020) which is dominated by old growth secondary forests. The other five species of tiger beetles from Davao City, viz., Prothyma (Symplecthyma) heteromallicollis heteromallicollis (Horn, 1909), Tricondyla aptera punctipennis (Chevrolat, 1841), Neocollyris (Heterocollyris) similior (Horn, 1893), Therates fasciatus quadrimaculatus (Horn, 1895), and Therates fulvipennis everetti (Bates, 1878) were documented in a pristine lowland secondary forests in Calinan and Baguio districts.

CONCLUSION & RECOMMENDATION
Davao Region hosts a good number of tiger beetles with 22 species record with 64% endemism (Table 1). Five (23%) are listed as threatened species, which calls for immediate conservation efforts. The astonishing number of tiger beetles in the remaining green spaces of Davao City is a testament to the importance of keeping the urban that houses tiger beetles and other animal species. Tiger beetles of Davao Region show consistent habitat preferences to forested and riverine ecosystems. In the face of deforestation and conversion of forest habitats, tiger beetles, which are linked with forested habitats, are highly at risk of extinction. This calls for more expeditions and inventories to assess extant populations leading towards conservation.