Cockroaches (Insecta, Blattodea) from caves of Polillo Island (Philippines), with description of a new species

Cockroaches collected during a protracted series of fieldwork in several limestone caves in Polillo Island, Philippines were taxonomically studied. A new species of Nocticola (Nocticolidae), N. gonzalezi Lucañas & Lit, sp. n., is described. The male of Periplaneta banksi Hanitsch (Blattidae) is described for the first time. Altogether, the present cave cockroach fauna of the island consists of six species.


Introduction
Cockroaches are well represented in cave ecosystems. They are classified as: trogloxene, troglophile, guanobyte or troglobiont depending on their specialization or adaptation to the cave environment (Chopard 1936, Roth andWillis 1960). Juberthie (2000) estimated that there are at least 31 species of troglobiont or obligate cavernicolous cockroaches worldwide but additional species are still waiting to be described.
Unfortunately, very few studies have been conducted regarding the diversity of Philippine cockroaches, maybe because the group includes species that are considered household pests. Thus, limited information is available on the country's fauna, especially in cave ecosystems. In recent years, the increasing interest in cave studies in the country has provided an opportunity to study the diversity of cockroaches in Philippine limestone caves.
The first documented troglobiont cockroaches in the Philippines were species of Nocticolidae from Rizal Province (Bolivar 1982), a few kilometers to the east of what is now Metro Manila. These were: Nocticola simoni Bolívar, 1892 (from a cave in San Mateo town), and Nocticola caeca Bolívar, 1892 (from Cueva de Talbac, in what is now Antipolo City). Roth (1988) also noted an unidentified Nocticola nymph from a cave in Montalban town (now called Rodriguez), also in Rizal Province, deposited in the Natural History Museum, Geneva, Switzerland.
Unfortunately, due to the limited knowledge on Philippine cockroach diversity, many species have often been misidentified. Encinares and Lit (2014) listed species found in caves in Polillo, including what they initially identified as Cryptocercidae sp. and Blattidae spp. 1, 2, 3 and 4. Lucañas et al. (2015) later clarified their identities to be Pycnoscelus striatus (Kirby, 1903) and Hemithyrsocera sp. Mag-usara and Nuñeza (2014) reported Polyzosteria limbata Burmeister, 1838, Calolampra irrorata (Fabricius, 1775), Methana marginalis (Saussure, 1864) and Ellipsidion sp. from several caves in Siargao, Surigao del Norte. Although, we were not able to examine the specimens, it is likely that those cockroaches have been misidentified as the mentioned species are all restricted to Australia. Similarly, Polyzosteria and Eublaberus sp. have been reported from a cave in Lanao del Norte (Macud andNuñeza 2014, Sobrepeña and, which are known only from Australia and the neotropics, respectively.
Other than those, there have been very few studies regarding the diversity of cockroaches in caves. This paper provides a list of cockroaches collected from several caves in Polillo Island, Quezon Province in the Philippines.

Materials and methods
All examined specimens were either pinned (for larger specimens) or preserved in vials of 95% ethyl alcohol, unless otherwise indicated as mounted on slide using Canada Balsam. Slide preparations were made starting with cold maceration by soaking in 10% aqueous Potassium Hydroxide (KOH) solution for 24 hours at ambient room temperature. They were then washed in distilled water to remove unwanted undissolved internal contents, and then run through graded alcohol series and then anhydrous clove oil to remove excess ethanol. Finally, they were mounted on microscope slides using Canada Balsam. The following parameters were measured using a calibration micrometer for pinned specimens and calibrated ocular micrometer for slide mounted specimens:

TL
(Total length) the length from the tip of the vertex (if exposed) or pronotum up to the tip of the tegmina at rest; BL (Body length) the length from the tip of the vertex (if exposed) or pronotum up to the tip of the subgenital plate (in case of brachypterous/micropterous/ apterous species, total length = body length); Pn Pronotum length × width along the longest axis; Tg Tegmina length along the longest axis.
Standard deviations for each measurement were also noted. Terminologies used for male genitalia follow Klass (1977), and Roth (2003) for other characters such as fore femoral armaments (Type A (robust spines terminating to 2-3 terminal spines), B (several proximal spines followed by row of smaller spinules with 2-3 terminal spines) and C (row of piliform spinules with 1-2 terminal spines).
Illustrations were made by tracing printed photomicrographs of clear slide-mounted specimens. The degree of sclerotization and pigmentation was made through line thickness and by stippling. All specimens are deposited in the Entomological Collection of the UPLB-MNH.  Diagnosis. Male brachypterous; female apterous. Compound eyes reduced, much smaller in female. Femur Type C 1 . Tarsi simple, symmetrical. Tergal gland absent (simoni-species group). Accessory hook-like phallomere (L2d) dagger-like. Roth (1988) noted the difficulty in separating nocticolid genera. Although Chopard (1945Chopard ( , 1966, being unable to differentiate Nocticola from Alluaudellina Chopard, 1932 noted the possibility of the two being synonyms, Nocticola differs from the latter by the absence of styles. Aside from Nocticola, only Cardacus Strand, 1928 lacks style in the family. The former is distinguished from the latter by the absence of ocelli and exposed vertex. Following such dichotomy, this new species is placed under Nocticola.

Taxonomy
This species can be distinguished from other troglobiotic Nocticola by the presence of an accessory hook-like phallomere which was only reported from two epigean species, N. scytala Andersen & Kjaerandsen and N. clavata Andersen & Kjaerandsen from Ghana, West Africa (Andersen and Kjaerandsen 1995). This species is similar to N. simoni and N. caeca in terms of coloration but differs in terms of size, N. gonzalezi being smaller. Unfortunately, the male genitalia of N. simoni and the male of N. caeca was not described by Bolivar (1892) and the location of the type specimens are unknown (Paris 1993).
Many Nocticola species are narrow endemics even among caves within a contiguous area (e.g. N. simoni was collected from a cave in San Mateo, Rizal Province and N. caeca from nearby Antipolo, also in Rizal Province). Considering this, as well as the morphological characteristics and the isolation of Cave 5 in Puting Bato, Burdeos, Polillo Island, we iterate the distinctness of N. gonzalezi.
Nymphs. Similar to female. Opaque white. Eyes reduced to 3-4 distinct facets.
Etymology. The species is named after Dr. Juan Carlos T. Gonzalez, the current director of the UPLB-MNH, in recognition of his pioneering efforts toward biodiversity documentation and conservation in the Polillos, a group of islands, east of Luzon and politically a part of Quezon Province.
Distribution. Philippines: Polillo Island. Ecology. Collected only from a single cave in Burdeos, Polillo Island, Quezon. The cave is deposited with porous calcite rocks and thin guano deposits from periodical roost of insectivorous bats, Hipposideros coronatus (Peters, 1871) and Miniopterus schreibersii (Kuhl, 1817). The site is relatively dry and rocky compared to the damp and sticky clay that is found throughout the rest of the cave, especially during the rainy season. They are quite fast and usually hide among the holes in the calcite rocks. They are found among and probably serve as prey for nymphs of whipspiders (Arachnida: Amblypygi), whipscorpions (Thelyphonida) and adult short-tailed whipscorpion (Schizomida).
Conservation status. Due to the narrow distribution of this species, it is suggested that the species be considered "Vulnerable" and that the cave from which it was collected be protected from further anthropogenic disturbances.
Female. Similar to male except that supra-anal plate rounded with deep division. Subgenital plate valvular.

Distribution. Philippines, Taiwan
Ecology. This is the first record of the species inside caves. The species is abundant and most individuals hid among the crevices of the cave walls. They were found from the twilight to the dark zone. Nymphs and mating pairs were often seen, suggesting that the species can complete their life cycle within the cave. Despite that, P. banksi is classified as troglophilic because of the lack of distinct troglobiotic characters and the possibility of the species surviving outside cave conditions. Both nymphs and adults are possibly preyed upon by whipspiders, Charon sp., and huntsman spiders, Heteropoda sp. Remarks. Hanitsch (1931) described P. banksi from a single female specimen from the Philippines without any further details on its collection locality. Asahinai (1980) later described another female specimen from Taiwan. This is the first time the male of this species is described.
The species resembles P. lata (Herbst, 1786), but differs primarily by its larger size. Bruinjing (1948) noted the possibility of the two species being synonyms, but a detailed examination of the male genitalia of P. lata is needed to confirm this.
Female. Almost similar to males except larger and robust. Wing size highly variable. Subgenital plate entire.
Distribution. Malaysia (Malacca), Indonesia (Sumatra, Kalimantan), Philippines. Ecology. McClure (1965) noted that P. striatus reaches very high population density, reaching up to 3000/m 2 of guano on Batu Caves, Malaysia. Similarly, individuals from Cave 3-4 form dense populations in thick guano from the fruit bat Rousettus amplexicaudatus (Geoffroy, 1810), but are also found in small population on dark zone with thin guano from insectivorous bats. They classified as guanobytes as they burrow beneath layers of guano. They are found together with and may serve as prey to Phlogiellus kwebaburdeos Barrion-Dupo et al., 2014(Barrion-Dupo et al. 2014, Rasalan et al. 2015, scutigerid centipedes, Scutigera sp. and some whipspiders, Charon sp. Remarks. Roth (1998) reported a female specimen collected from bat guano in Manhuyod or Negros. Roth temporarily assigned it as Pycnoscelus sp C. due to the absence of a male specimen, but stated that it closely resembles P. striatus. The specimen is deposited in the Zoological Institute, Department of Systematics, Lund, Sweden. Several specimens collected from Burdeos have the same interocular width as Pycnoscelus sp. C (2.3mm), while some fit with P. striatus (1.5-1.7mm). Therefore, it is possible that Pycnoscelus sp. C is a variation of P. striatus. Additional specimens, particularly from the same collection locality of Pycnoscelus sp. C, are needed to confirm this.
The foregoing description of the right style (i.e. rounded apically) differs from that of Roth (1998), which he illustrated as acute apically.
Ecology. The species was collected on thick guano piles of mix bat populations in Cave 2. In contrast with P. striatus, the species was present only on the top layer of the guano and does not burrow much even if disturbed. Remarks. This species or form is closely similar to P. striatus and may prove to be only a variation. For now, it is treated separately because of its darker coloration, robust abdomen, rather convex body, large arolia and the presence of narrow anterolateral band on its pronotum. The absence of a male specimen hinders further identification. Roth (1998) described unverified species of Pycnoscelus and temporarily assigned them as spp. A, B and C. In order to avoid confusion, this specimen is temporarily named as Pycnoscelus sp. D.
Remarks. Accidentals. Since only one female specimen was collected and troglomorphic characters are absent, it can be said that its presence in the cave was accidental. Roth (1990) described Shelfordina philippensis from Camarines Sur, but later transferred it to the genus Margattea (Roth 1996). Both genera are morphologically similar except for the armature of the fore femora, i.e., type A for Shelfordina and B for Margattea, and the presence of tergal gland on the eighth abdominal segment in males of Margattea.

Subfamily Blattellinae Karny, 1908 Genus Hemithyrsocera Saussure, 1893
Hemithyrsocera sp. Description. Front femur A2, pulvilli on 4 proximal tarsomeres, tarsal claw simple and symmetric, arolium present. Quite similar to nymphs of H. silbergliedi except for the broad lateral white margin of the pronotum and completely black abdomen.
Remarks. Accidentals. This species has been previously recorded only from Bulalon Cave (Lucañas et al. 2015) with only a few early instar nymphs collected inside the cave. Even though H. silbergliedi (Roth, 1985) is abundant outside the caves, the slight differences in pronotal coloration and the absence of adult specimens hinders further identification.