Bullanga florida ( Navás, 1913 )

Zheng, Yuchen & Liu, Xingyue, 2020, First description of immature stages of the antlion Bullanga florida (Navás, 1913) (Neuroptera, Myrmeleontidae, Dendroleontini), Zootaxa 4858 (3), pp. 394-404 : 395-401

Bullanga florida ( Navás, 1913)

( Figs 1–19 )

Glenurus floridus Navás 1913: 11 . Type locality: China (Zhejiang: Ningbo ).

Diagnosis of 3rd instar larva. Medium-sized antlion larva ( Table 1). Head mostly dark brown. Generally yellowish brown; some dark brownish markings and numerous dark brownish spots present on thorax and abdomen. Setae disposed on body mainly black. Plumose hairs relatively long and extremely slender ( Fig. 6 ), present on lateral portions of thorax and abdomen.

Head. Subrectangular in dorsal view, longer than wide. Clypeo-labrum dark brown in dorsal view; anterior margin slightly concaved and covered with a row of dolichasters. Head capsule mostly dark brown, anterior and posterior parts slightly darker in dorsal view; dolichasters short and sparse on dorsal part; lateral setae relatively long and dense; ventral part of head capsule with a few brownish markings, which are completely lost in some individuals. Antennae long and thin, composed of at least 18 flagellomeres. Ocular tubercles black and small, relatively prominent. Mandibles mostly orange, but dark brown on basal and distal portions; mandibles upturned but relatively straight, similar in length to head capsule, equipped with three pairs of comparatively large teeth, which is orange but gradually darkened distad; second tooth longer than first tooth, third tooth slightly longer than second tooth; 2–4 dolichasters present on basal part of mandibles; three relatively long interdental mandibular setae present anterior to above dolichasters and posterior to first tooth; two interdental mandibular setae between first and second teeth; 1–2 interdental mandibular setae between second and third teeth; external margin of mandible with a group of stout setae at base. Labial palps dark brown, elongated.

Thorax. Pronotum covered with sparse short conical setae dorsally, lateral margin with relatively long stout setae and slender setae; a pair of dark brownish markings present at middle of pronotum, anteromedially diffuse. Mesothorax with spiracles present on stout dark brownish sclerotized tubercle ( Fig. 6 ); mesonotum with a tubercle at middle, bearing a tuft of long hair-like black setae, and with prominent setiferous processes, anterior one longer, relatively inflated distally ( Fig. 6 ). Metathorax with slightly protruding setiferous processes. A few spots present on ventral part of each thoracic segment.

Legs. Greenish yellow, covered with short stout black setae and long slender black setae; fore and meso coxae with indistinct brown markings.

Abdomen. Yellowish brown, with numerous dark brown spots dorsally, segments I–VIII each with a pair of dark brown markings along midline in dorsal view. Venters of segments II–VIII each with a pair of dark brown oblique wide stripes at middle; segments I–VII with a few dark brown spots between preceding stripes. Abdominal spiracles dark brown, not prominent on segments I–VII, but slightly prominent on segment VIII. Segment IX broadly subtrianglar, longer than wide, covered with long setae; two pairs of weakly developed digging setae present on apex of segment IX ventrally ( Fig. 8 ).

Description of pupa. Body C-shaped. Pale yellow, covered with yellowish brown setae except wing pads. Mandibles dark reddish brown. Antennae stretching posterior to compound eyes. Pretarsal claws not curved backward basally. Wing pads with scattered brown spots. Abdomen with numerous irregular brown markings.

Material examined. 30 larvae and 2 pupae: 1 3rd instar larva preserved in 95% ethyl alcohol, 3 3rd instar larvae reared to adults (2♂ 1♀), China: Fujian, Longyan, Jiangshan town, Jiangshan Grand Canyon Scenic Spot [ũmkẖ Ĩṇēṉ], 750 m, 15.III.2020, Yuchen Zheng ( CAU); 1 3rd instar larva reared to adult (1♀) , 1 pupa reared to adult (1♂), China: Fujian, Longyan, Jiangshan town , Jiangshan Grand Canyon Scenic Spot , 640 m, 30.IV.2020, Yuchen Zheng ( CAU); 1 3rd instar larva reared to adults (1♂), China: Fujian, Longyan , Yanshi Town , Mt. Tiangongshan [ƙäm], 710 m, 15.III.2020, Yuchen Zheng ( CAU); 1 3rd instar larva preserved in 95% ethyl alcohol, 1 2nd instar larva reared to 3rd instar, 2 3rd instar larvae reared to adults (2♂), China: Fujian, Longyan , Yanshi Town , Mt. Tian- gongshan, 900 m, 9.IV.2020, Yuchen Zheng ( CAU); 1 3rd instar larva still rearing, China: Fujian, Longyan , Yanshi Town , Mt. Tiangongshan , 970 m, 3.V.2020, Yuchen Zheng ( CAU); 1 3rd instar larva preserved in 95% ethyl alcohol, 1 2nd instar larva reared to 3rd instar, China: Fujian, Quanzhou , Dehua County, Shuikou Town , Mt. Shiniushan [. +m], Geyao [be], 1100 m, 16.IV.2020, Yuchen Zheng ( CAU); 1 3rd instar larva stored in 95% ethyl alcohol, 3 3rd instar larvae reared to adults (1♂ 2♀), China: Fujian, Quanzhou, Dehua County , Shuikou Town , Mt. Shiniushan , Bangshang Village [8±ḣ], 1300 m, 16.IV.2020, Yuchen Zheng ( CAU); 2 3rd instar larvae preserved in 95% ethyl alcohol, 1 2nd instar larva reared to 3rd instar, 2 3rd instar larvae reared to adults (2♂), 6 3rd instar larvae still rearing , 1 pupa in cocoon reared to adult (1♀), China: Fujian, Quanzhou, Dehua County, Shuikou Town , Mt. Shiniushan , near north gate entrance of scenic spot, 1380 m, 18.IV.2020, Yuchen Zheng ( CAU); 1 3rd instar larva preserved in 95% ethyl alcohol, 1 3rd instar larva still rearing, China: Fujian, Zhangzhou , Nanjing County , Jinshan Town , Exiandong Natural Scenic Spot [Ȇüṳhṋṇēṉ], 520 m, 3.V.2020, Yuchen Zheng ( CAU) .

Bio-ecology. Based on field observation of the specimens we collected at four localities, we found that the B. florida larvae inhabit four types of habitats. Habitat I ( Fig. 13 ): 15 larvae (13 3rd instar, two 2nd instar) and two cocoons were found on some large rock and protruding rock wall platforms which are sheltered, dry, and covered with a thin layer of sand and other detritus. In this habitat, B. florida larvae anchor themselves on these rocks and platforms. Similarly to other Dendroleontini species, they are not pit builders, but hide themselves under a thin layer of sand and detritus, only exposing their jaws. Habitat II ( Fig. 14 ): four larva (three 3rd instar, one 2nd instar) were found living under small (<20 mm) stone slabs and fallen leaves with a few coarse sand on the oblique rock walls which with abundant lichens growth. They were found only exposing their jaws outside under the stone slabs, covered with less sand and debris compared with other habitats. Habitat III ( Fig. 15 ): Five larvae (all 3rd instar) were found living under medium-sized (<250 mm) stones that are located on the dry protruding rock wall platforms, covered with a thin layer of detritus. Habitat IV ( Fig. 17 ): Six larvae (five 3rd instar, one 2nd instar) were found in artificial environment, living on the cement platform of road drains in mountains and on the cement floor of an abandoned log cabin, covered with a thin layer of sand and other detritus. From all of above habitats, more than one larvae specimen were found to co-occur and often in a limited space, but no cannibalism was observed. We also noticed that the larvae of B. florida often coexists with the pit-builder larvae of Myrmeleon bimaculatus Yang, 1999 in some localities of Fujian, China.

We found various arthropod remains as probable prey of the B. florida larvae from all above habitats, such as dirt-colored seed bugs ( Rhyparochromidae ), ground beetles ( Carabidae : Pterostichini ), darkling beetles ( Tenebrionidae : Opatrini ), ants ( Camponotus spp.), and stone centipedes ( Lithobiidae ) ( Fig. 16 ).

We also observed the predation behavior of the B. florida larva in natural condition. In habitat I, an ant ( Camponotus sp.) was captured when crawling on the thorax of a B. florida larva, where it was probably detected thanks to the thoracic hair-like setae. After the prey was detected, the larva whipped its head back rapidly, hit the ant, and seized it by inserting its jaws to pierce the ant’s body.

Under artificial conditions (such as turning them over, or remove sand and detritus from the larval body), they could recede into the sand and detritus or feign death for about 1.5–6.0 minutes, and then started walking forward to find new suitable habitat in which to hide themselves.

As the lab-reared larvae we studied were collected near the emergence period of adults, the 3rd instar larvae were fed only once. After about 10–38 days the 3rd instar larvae began to spin a spherical cocoon covered by a layer of sand and other detritus for pupation; the cocoon was firmly attached to rock ( Fig. 11 ). After about 15–42 days, adults emerged, which usually took place after nightfall.

Figures

FIGURES 1–3. Bullanga florida (Navás, 1913), 3rdinstar larva, habitus photos. 1. dorsal view; 2. ventral view; 3. lateral view. Scale bar: 2.0 mm.

FIGURES 4–8. Bullanga florida (Navás, 1913), 3rd instar larva. 4. head, dorsal view; 5. head, ventral view; 6. thorax, dorsal view; 7. abdominal segments VII–IX, dorsal view; 8. abdominal segments VII–XI, ventral view. 1t: first tooth; 2t: second tooth; 3t: third tooth; Ims: interdental mandibular setae; D: dolichaster; Ms: mesothoracic spiracles; Ph: plumose hair; Msp: mesothoracic setiferous processes; Wdds: weakly developed digging setae; VIII-As: VIII abdominal spiracles. Scale bar: 2.0 mm.

FIGURES 9–12. Biological photos of Bullanga florida in immature stages. 9. 3rd instar larva in habitat I; 10. 3rd instar larva feeding on woodlice (Porcellio sp.) in artificial feeding habitat; 11. cocoon; 12. pupa.

FIGURES 13–17. Habitats of Bullanga florida (Navás, 1913). 13. habitat I; 14. habitat II; 15. habitat III; 16. corpses of larva leftover in habitat III; 17. habitat IV. Red arrows indicate the positions where the larvae were collected; blue arrow indicates the position where the corpses were found in habitat III.

FIGURES 18. Bullanga florida, live adult.

FIGURES 19–20. Adult habitus photos. 19. Bullanga florida (Navás, 1913); 20. Dendroleon esbenpeterseni Miller & Stange, 1999.