Tiger beetles (Coleoptera, Cicindelidae) of Northern Mindanao region (Philippines): checklist, distributional maps, and habitats

Abstract The knowledge about tiger beetle fauna of the Northern Mindanao region (Philippines) is summarized based on literature data and new records. Thirty species classified in ten genera (Tricondyla, Neocollyris, Protocollyris, Therates, Prothyma, Heptodonta, Thopeutica, Lophyra, Calomera, and Cylindera) were documented from the area (56% of tiger beetle fauna of Mindanao and 21% of Philippine species). Twelve species were noted from Northern Mindanao region for the first time, including five taxa, Neocollyris speciosa, Calomera angulata, Cylindera minuta, Lophyra striolata tenuiscripta, and Thopeutica virginea, not recorded from Mindanao before. Distribution maps for all recorded species and the first photographs of habitats for some species in Mindanao and/or in the Philippines are provided. Eight species (27% of recorded fauna) were noted from riverine habitats while 18 tiger beetles (60%) were typical forest taxa; in the case of four species, their habitats in Northern Mindanao region are not known.


Introduction
Tiger beetles (Coleoptera: Cicindelidae) are a beetle family (López-López and Vogler 2017; Duran and Gough 2020) of more than 2850 species distributed world-wide, but with the larger number of taxa occurring in tropical regions (Cassola and Pearson 2000;Wiesner 2020). With 162 taxa (including 144 species) actually known from the country the tiger beetle fauna of the Philippines is recognized as one of the most diverse in the world (Cabras et al. 2016a;Dheurle 2016Dheurle , 2019Zettel and Pangantihon 2017;Zettel and Wiesner 2018;Anichtchenko andMedina 2019, 2020;Medina et al. 2019Medina et al. , 2020Görn 2020). Moreover, it can be characterized by high percentage of endemic species as more than 85% of Cicindelidae are noted only from this country (Cassola and Pearson 2000;Cabras et al. 2016a;Dheurle 2016Dheurle , 2019Zettel and Pangantihon 2017;Zettel and Wiesner 2018;Anichtchenko andMedina 2019, 2020;Medina et al. 2019Medina et al. , 2020cGörn 2020), with particular species often noted only on single islands (Cabras et al. 2016a). It can be expected that such high diversity values results from both geographical location of the country in the tropical region as well as the occurrence of a large number of geographically isolated islands that influence the evolution of endemic species.
In the present paper we focus on the region of Northern Mindanao where no regular studies on tiger beetle species were previously done. As a result, the first checklist of Cicindelidae occurring in this region as well as distributional maps for all known species occurring in the area, and photographs of habitats for the 12 recorded taxa are provided. This paper may serve as a baseline for further studies on this beetle family not only in the Northern Mindanao but also in other regions in the country.

Materials and methods
Northern Mindanao geographically lies within latitude 7°15' to 9°15'N and longitude 123°30' to 125°30'E, is bound on the north by the Bohol Sea, on the west by Zamboanga provinces, on the east by Agusan and Davao provinces, on the south by Lanao del Sur and Cotabato. The whole region covers a total land area of 19,279.60 km² and more than 60% of the region's area are classified as forest land. Geologically, this region is formed of a combination of coastal areas, rivers, falls, volcanoes, highlands with flat terrain, rugged and faulted mountains with rich soil, abundant minerals, and agricultural resources. Since the region is located outside the typhoon belt area, rainfall is evenly distributed throughout the year (Dejarme-Calalang and Colinet 2014; Bouquet 2017). Northern Mindanao comprises five provinces: Bukidnon, Camiguin, Lanao del Norte, Misamis Occidental, and Misamis Oriental (Figure 1). Regular studies were done in sixteen sampling sites in the Northern Mindanao region, including riverine areas, secondary forests, and coastal areas (Table 1,  , and most of the tiger beetle material used in this study was collected using entomological hand nets during field work in 2017-2019. Some additional data were provided from earlier studies, including published data (Wiesner 1988;Naviaux 1994Naviaux , 2002Cassola 2000Cassola , 2011Dheurle 2015Dheurle , 2017Cabras et al. 2016a;Görn 2020).  Literature data for Northern Mindanao. Bukidnon province: Impasung-ong (Cabras et al. 2016a).
Habitat. Forest species found on vertical and fallen tree trunks, sometimes in forest floor; occasionally also outside the forest (but close to the trees).
Remarks. Larva of nominal subspecies was described by Trautner and Schawaller (1996), who observed it hunting during night period in the bark of tree (e.g., Samanea saman). Figure 6B General distribution. Species endemic to the Philippines, where it was recorded from Luzon, Visayas, and Mindanao; in Mindanao recorded only in Northern Mindanao, Davao, and Bangsamoro Autonomous Region in Muslim Mindanao regions (Cabras et al. 2016a, b;Marohomsalic et al. 2021).
Habitat. Forest, arboreal species found on vertical and fallen tree trunks.

Tricondyla (Stenotricondyla) cavifrons Schaum, 1862
Habitat. Forest, arboreal species found on vertical and fallen tree trunks. Marohomsalic et al. (2021) recorded native and invasive tree species having extrafloral nectaries as favorite hunting areas for this species.
Habitat. Forest, arboreal species found on vertical and fallen tree trunks and leaves of different bush species.
Habitat. Forest, arboreal species found on vertical and fallen tree trunks and leaves of different bush species. Figure 7B General distribution. Species noted from Borneo, Indonesia, Malaysia, and Philippines, where it was found in Mindanao and Palawan; in Mindanao recorded only in Northern Mindanao region (Cabras et al. 2016a).
Habitat. Forest, arboreal species found on vertical and fallen tree trunks and leaves of different bush species.
Habitat. Forest, arboreal species found on vertical and fallen tree trunks and leaves of different bush species.  Table 1; photographs DAPA).  Table 1; photographs A, C-H DAPA, B RJ).

Neocollyris (Heterocollyris) similior (Horn, 1893) Figures 4D, 7D
General distribution. Species endemic to Philippines where it was recorded only from Mindanao (Naviaux 1994;Cabras et al. 2016;Marohomsalic et al. 2021). Habitat. Forest, arboreal species found on vertical and fallen tree trunks and leaves of different bush species. Figure 7E General distribution. Species endemic to the Philippines, where it was noted only from Luzon, Mindoro (Cabras et al. 2016a), and Mindanao (new record).
Habitat. Forest, arboreal species found on vertical and fallen tree trunks and leaves of different bush species.
Material examined. Bukidnon province: Mt. Kitanglad, 28.07.1990 Habitat. Forest species noted on tree trunks and leaves. Remarks. When disturbing, actively fast flying among trees; during flight shows bright orange abdomen coloration. Taxonomical status of both subspecies of Therates coracinus noted in Mindanao (spp. coracinus and ssp. fulvescens Wiesner, 1988) should be revised including molecular data as they probably represent separate species or synonyms.

Therates fasciatus fasciatus (Fabricius, 1801) Figures 4D, 8B
General distribution. Subspecies known from Indonesia and Philippines. In the Philippines recorded only from Mindanao and Palay islands (Cabras et al. 2016a); from Mindanao Island it was known only from Davao and Northern Mindanao regions (Cabras et al. 2016b).
Literature data for Northern Mindanao. Bukidnon province: [no detailed locality] (Wiesner 1988).   Habitat. Forest species noted on tree trunks and leaves.

Remarks.
Taxonomical status of all three subspecies of Therates fulvipennis noted in Mindanao (spp. bidentatus Chaudoir, 1861, ssp. fulvipennis Chaudoir, 1848, and spp. everetti Erichson, 1834) should be revised including molecular data as probably at least some of them represent separate species or synonyms.

Subtribus Dromicina Thomson, 1859
Genus Prothyma Hope, 1838 The genus Prothyma is represented in the Philippine islands by 12 species, including six recorded from Mindanao Island (Cabras et al. 2016a). Habitat. Species found on shaded forest paths and forest litters. Remarks. Some individuals were observed resting on undershrub leaves along forest trails.

Genus Heptodonta Hope, 1838
The genus Heptodonta is represented in the Philippine islands by five species, including two recorded from Mindanao Island (Cabras et al. 2016a;Görn 2020).  General distribution. Species endemic to the Philippines, where it has been noted on Mindanao and Panay islands only; in Mindanao it was noted in Davao, North Mindanao, and Soccsksargen regions (Cabras et al. 2016a;Cabras and Wiesner 2016;Görn 2020;Medina et al. 2020c;Medina 2020;Pepito et al. 2020).

Subtribe Cicindelina Latreille, 1802
Genus Calomera Motschulsky, 1862 The genus Calomera is represented in the Philippine islands by five species, including four recorded from Mindanao Island (Cabras et al. 2016a). Three of them have been noted from the Northern Mindanao region. Habitat. The species occurs on sandy river banks exposed to direct sunlight (pers. obs.). Remarks. First records both from Northern Mindanao region and entire Mindanao Island. This species was observed to co-occur with Calomera mindanaoensis, C. lacrymosa, Cylindera discreta elaphroides, and C. minuta. Figure 9A General distribution. Species endemic to Philippines where it was found only in Mindanao (Northern Mindanao region) (Cassola 2011;Cabras et al. 2016a).
Habitat. Species noted from river banks.  Habitat. The species occurs on sandy river banks (pers. obs.).

Remarks.
At least in some areas Calomera lacrymosa seems to occur sympatrically or even syntopically with C. mindanaoensis (pers. obs.). C. lacrymosa was recently noted as a host of Hexathrombium parasitic mites (Acari: Microtrombidiidae) (Acal et al. in press). Habitat. The species was recorded as the most opportunistic according to habitat type among all Cicindelidae presented in this paper, found on sandy river banks, forest paths, coastal area, and unused compost pit near the river (pers. obs.).

Calomera mindanaoensis (Cassola, 2000)
Remarks. At least in some areas co-occur with C. lacrymosa. C. mindanaoensis was recently noted as a host of Hexathrombium (Acari: Microtrombidiidae) parasitic mites (Acal et al. -in press). This species was also observed resting on undershrub plants along the trails during rainy season.

Genus Lophyra Motschulsky, 1859
The genus Lophyra is represented in the Philippine islands by one species, known to occur also in Mindanao Island (Cabras et al. 2016a). Habitat. Collected along the trails of coconut field (Municipality of Bacolod, Lanao del Norte) and from cultivated corn and ginger field (Municipality of Sinacaban, Misamis Occidental) (Acal -pers. obs.).

Genus Thopeutica Chaudoir, 1861
The genus Thopeutica is the largest tiger beetle genus in the Philippines with 31 species classified in two subgenera described to date, including 27 species in subgenus Thopeutica s. str. and four species in subgenus Philippiniella (Cabras et al. 2016a, 2020c. Thopeutica is geographically restricted to Sulawesi and the Philippines and is one of the most exclusive genera since all except two species know from the country seem to be restricted to only one island or to very few islands (Cassola and Zettel 2006). Figure 9E General distribution. Species endemic to the Philippines, where it was recorded from Leyte, Mindanao, and Samar; according to Cabras et al. (2016a) only general distributional data from Mindanao for this species were known, this is the first record from Northern Mindanao region.
Habitat. The only specimen from Northern Mindanao studied was collected in a shaded riverine area. Figure 9F General distribution. Species endemic to the Philippines, where it was recorded from Luzon and Mindanao; in Mindanao recorded till now only from Northern Mindanao region (Cabras et al. 2016a).
Habitat. No detailed data on habitat specificity in Northern Mindanao region but most probably occurring along rivers in shaded areas. Figure 10A General distribution. Species endemic to the Philippines, where it was recorded from Leyte, Luzon (?), Mindanao, and Samar; in Mindanao noted only from Northern Mindanao region (Cabras et al. 2016a).
Habitat. No detailed data on habitat specificity in Northern Mindanao region but most probably occurring along rivers in shaded areas. Figure 10B General distribution. Species endemic to Philippines where it was recorded only from Luzon (Cabras et al. 2016a) and Mindanao (new record) islands.
Habitat. No detailed data on habitat specificity in Northern Mindanao region but most probably occurring along rivers in shaded areas.

Genus Cylindera Westwood, 1831
The genus Cylindera is represented in the Philippine islands by 22 species, including five recorded from Mindanao Island (Cabras et al. 2016a).

Subgenus Eugrapha Rivalier, 1950
Cylindera (Eugrapha) minuta (Olivier, 1790) Figures 2G, 3A, C-E, 5F, 10C General distribution. Species recorded till now from Bangladesh, Brunei, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Philippines, Thailand, and Vietnam (Wiesner 1992). According to Cabras et al. (2016a) in the Philippines it is known only on the basis of general distributional data; here we present the first records of this species from Mindanao. Habitat. A riverine tiger beetles species recorded on sandy bank (per. obs.).
Remarks. Although C. discreta elaphroides is active mainly during sunlight hours on the river banks, it was also noted as species actively hunting during heavy rain on vertical surfaces (Cabrera et al. 2019). Some specimens were also observed resting on the leaves of Pennisetum sp. along the river (pers. obs.).

Cylindera (Ifasina) mouthiezi Dheurle, 2015 Figures 2H, 10E
General distribution. Species endemic to Philippines (Cabras et al. 2016) where it has been recorded only from Mindanao, where it was found only from Davao and Northern Mindanao regions till now (Dheurle 2015(Dheurle , 2017Cabras et al. 2016b). Habitat. All specimens known for us from Northern Mindanao region were collected in a shaded riverine area.
Remarks. This species co-occurs with Cylindera discreta elaphroides and Thopeutica angulihumerosa. Figures 3G, 10F General distribution. Species recorded from Bangladesh, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Papua New Guinea, Philippines, Thailand, Vietnam; in the Philippines is was noted from the following islands: Leyte, Mindanao, Palawan, and Tawi-tawi; in Mindanao recorded only on the basis of general information (Cabras et al. 2016a); here we provide the first records from Northern Mindanao region.
Provisional key to tiger beetle species known to occur in the Northern Mindanao Region

Discussion
Tiger beetle fauna of Northern Mindanao vs. fauna of the entire island and country Thirty species (including two with two subspecies each) classified in ten genera are actually known from Northern Mindanao region (  Table 2). The number of recorded Cicindelidae taxa seems to depend on the surface area of the province, as Bukidnon is the largest one and Camiguin is the smallest area. Since not all types of habitats were studied in particular provinces, additional tiger beetle species inhabiting in Northern Mindanao region are expected to be found with more extensive fieldwork in the future.

Tiger beetles and their habitats
Among Cicindelidae taxa recorded in Northern Mindanao region both epigeic (Calomera, Cylindera, Heptodonta, Lophyra, Prothyma, Thopeutica) and arboreal (Therates, Neocollyris, Protocollyris, Tricondyla) species were noted. Most of the epigeic species are recognized as riverine tiger beetles (all Calomera and most Cylindera except C. viduata, as well as Heptodonta nigrosericea, Lophyra, Thopeutica) occurring on sandy and sunny banks or on shaded banks of medium and large rivers. Among the epigeic Cicindelidae only Cylindera viduata, Prothyma heteromallicollis heteromallicollis, and some Lophyra striolata tenuiscripta were noted as forest beetles occupying different sandy areas. Our data from Northern Mindanao region confirm observations both from other regions of Mindanao (Cabras et al. 2016b;Cabras and Wiesner 2016;Medina 2020;Medina et al. 2020;Pepito et al. 2020) and different parts of the world including e.g., some regions of North America (Pearson et al. 1997), Africa (Jaskuła 2015;Jaskuła and Płociennik 2020), Asia (Dangalle et al. 2014) or Europe (Jaskuła 2011;Jaskuła et al. 2019), as tiger beetles are known to prefer riverine habitats not only because of adequate water and food resources but also for protection from predators and human disturbances (Bhargav and Uniyal 2008). In many regions of the world the highest diversity and species richness of epigeic tiger beetles are noted mostly on lowland areas that had a variety of habitats such as coastal areas, river banks, grasslands, and sand dunes attractive for tiger beetles (e.g., Pearson and Cassola 1992;Pearson et al. 1997;Jaskuła 2011Jaskuła , 2015Dangalle et al. 2014;Jaskuła et al. 2019;Jaskuła and Płociennik 2020).
On the other hand, in the tropical regions large number of Cicindelidae are typical arboreal taxa (e.g., Wiesner 1992;Pearson and Vogler 2001;Moravec 2007;Dangalle 2018) and large forests, especially natural ones, are characterized by high species diversity of such tiger beetles. In Northern Mindanao region, where more than 60% of its entire area is classified as forest land, 48% of all recorded Cicindelidae taxa are noted as arboreal taxa (Table 2). This number is expected to increase in the future as several additional arboreal species are known from other parts of Mindanao, including areas located close to the administrative border of Northern Mindanao region (Cabras et al. 2016a). Moreover, in case of some species, only general distributional data from Mindanao are known (e.g., Protocollyris okajimai Mandl, 1982, Neocollyris rugei Horn, (1892) N. erichsoni (Horn, 1892), N. chaudoiri (Horn, 1892) (Naviaux 1994)), it cannot be excluded that some of these taxa were collected (and actually inhabit) in the Northern Mindanao region. On the other hand it is necessary to note that many areas in Mindanao, including Northern Mindanao region, are under large impacts of human activities, and as a result many tiger beetle habitats are regularly destroyed. Forest destruction, including deforestation in all sorts and forms such as illegal logging, mining, agricultural expansion, quarrying, over-extraction of plant biota for fuel and other domestic uses, or conversion of land into human settlement are among the rampant problems in the area (Magdalena 1996;Carandang et al. 2012).

Conclusions
Present data on diversity and distribution of Cicindelidae of Northern Mindanao region clearly suggest that the area (especially riverine habitats and forests) is unique for tiger beetle fauna which includes a significant number of both species endemic to Mindanao and to the entire country. Moreover, the lack of data on Cicindelidae in many areas in Mindanao Island and in the country is evident, and for many species, only single records are known. As the region is characterized by a large mosaic of still poorly explored habitats (e.g., forests in the mountains, upper parts of river systems), and more than 12% of all species noted from Mindanao were discovered and described as new for science only during last two decades, it should be expected that future studies will provide many new and important distributional data and probably will describe new Cicindelidae taxa.