Pheropsophus aequinoctialis (Linné)

Frank, Howard, Erwin, Terry & Hemenway, Robert, 2009, Economically Beneficial Ground Beetles. The specialized predators Pheropsophus aequinoctialis (L.) and Stenaptinus jessoensis (Morawitz): Their laboratory behavior and descriptions of immature stages (Coleoptera: Carabidae: Brachininae), ZooKeys 14 (14), pp. 1-36 : 18-30

Pheropsophus aequinoctialis (Linné)

EGG ( Fig. 15 ). White. Rectangulate with moderately rounded apices. Surface polygonic, with numerous very close-spaced large perforations; micropore not obvious.

INSTAR I. Form. ( Fig. 16 ) Campodeiform planidium; head relatively small compared to prothorax, eyes absent. Frontale with three simple-tooth egg-bursters near base of head on frontale. Body setiferous dorsally, less so than in Stenaptinus (see above). Segment X (PY): sternite ( Figs. 16 , 24 ) medially with two widely spaced non-serrated recurved teeth and with seta PY7 normal. Urogomphi (cf. Fig. 16 ) absent.

Coloration. Mostly white color with creamy-colored head capsule and slightly rufescent mandibles darkened toward the tips.

Chaetotaxy. Head. ( Figs. 16 , 17, 18 ) Frontale ( Fig. 17 ) with 9 “ancestral” setae (FR1 – FR9, FR10 and 11 missing), and one auxiliary seta each side, and 2 pores (FRd – FRe, a, c, and f missing) left side, right side devoid of pores in specimen illustrated. Parietale ( Figs. 16 , 17 ) with 18 setae (PA1 – PA18) and 8 pores (PAa – PAl; pores d, f, g, h absent) each side. Antenna ( Figs. 16 , 17 ): antennomere 1 with 5 “ancestral” pores (ANa – ANe) and one auxillary pore (unlabeled); antennomere 2 absent or fused with 3; antennomere 3 with 3 “ancestral” setae (AN1 – AN3), one auxillary seta, and 1 pore (ANf), plus a dome-shaped hyaline sensillum; antennomere 4 with 4 setae (AN4 – AN7) and 1 auxillary seta, no pores, and 2 small apical sensilla. Mandible ( Fig. 17 ) falciform without setae and pores. Labium ( Fig. 18 ): prementum with 1 seta (LA3) and 1 pore (LAa) each side; palpomere 1 with 1 seta and 3 pores, none of which correspond to the “ancestral” schema; palpomere 2 with 1 apical sensillum. Maxilla ( Fig. 18 ): cardo without setae; stipes with 5 “ancestoral” setae ( MX 1 – MX 5), and 2 pores

(MXa – MXb), and no variable setae (gMX) on dorsal side; lacinia ( Fig. 18 ) with 1 seta ( MX 10); galeomere 1 with 1 seta ( MX 7) and no pores; galeomere 2 with 2 minute dorsal setae, no pores; maxillary palpomeres without visible sensatory features.

Thorax. Prothorax: Notum ( Figs. 16 , 19 ) with 1 identifiable major “ancestral” seta (PR 9) and numerous auxiliary setae (not labeled), PR 1 absent, and no pores. Epimeron ( Fig. 20 ) with 1 seta ( EP1 ), and no pores. Episternum and trochantin not defined. Prosternite ( Fig. 20 ) with 1 seta “ancestral” (Pt1) and one auxiliary seta; gPS absent.

Mesothorax and metathorax: Notum ( Figs. 16 , 19, 20 ) with 1 identifiable major “ancestral” seta (PR 9) and numerous auxiliary setae (not labeled), PR 1 absent, and no pores. Mesepisternum ( Fig. 20 ) with 2 setae (ES1, ES2) and no pores. Trochantin and epimeron not defined. Mesoprosterite ( Fig. 20 ) with 3 setae (Pt1, Pt2, Pt3) each side; metaprosternite with 3 setae (Pt1, Pt2, Pt3). Metepisternum with 3 setae (ES1, ES2, ES4).

Abdomen. Figs. 16 , 21 -24 . Tergite I ( Figs. 16 , 21 ) with possibly one “ancestral” seta (TE2) and numerous auxiliary setae (not labeled), and no pores. Tergites II – VIII as in

Tergite 1. Tergite IX, X and urogomphi ( Figs. 16 , 23 ), IX with 4 setae (UR8 – UR11) and no pores. Epipleurite IX ( Fig. 16 ) with 2 setae (EP1 – EP2) and no pores. Hypopleurite VII ( Fig. 16 ) with 2 setae (HY1 – HY2) and no pores. Segment VII sternite ( Fig. 24 ) with 5 setae (ST1 – ST5) each side and no pores. Segment IX sternite ( Fig. 24 ) with 3 setae (ST1 – ST3) each side and no pores. Segment X (PY) sternite ( Figs. 16 , 24 ) with 1 seta (ST1) each side, no pores. Medially with two wide-spaced nonserrated and recurved teeth ( Figs. 16 , 24 ).

Legs. ( Fig. 25 ) All legs stout, similar in proportions and setation; anterior leg slightly shorter than middle and posterior ones. Coxa with 7 setae (ancestral CO10 – CO17, with CO1-9 absent, and no pores. Trochanter with 5 setae (TR2 – TR5, and TR8) and one pore. Femur with 4 setae (FE2 – FE5) and no pores FEa and FEb. Tibia with 7 setae (TI1 – TI7) and no pores. Tarsus with 1 constant seta (TA1) and no pores. Claws simple, with no setae or tooth, symmetrical in shape and size.

INSTAR II. Form. (generally as in Fig. 35 ) Hypermetamorphic stage 2 instar.

Coloration. White; head capsule creamy-white with mouthparts slightly infuscated in part; mandibles piceous at tips.

Chaetotaxy. Head. ( Figs. 26-27 ) Frontale ( Fig. 26 ) with 7 “ancestral” setae (FR1 – FR7), and no pores. Parietale ( Figs. 26, 27 ) with 12 setae (PA3, PA5– PA7, PA9, PA11 – PA13, PA15 and PA17) and no pores. Antenna ( Figs. 26 ): antennomere 1 with one “ancestral” seta (AN1) and no pores. Dome-shaped hyaline sensillum absent. Mandible ( Fig. 26 ) falciform without setae and pores. Labium ( Fig. 27 ) without setae or pores. Maxilla ( Fig. 27 ): cardo without setae; stipes with 3 “ancestral” setae ( MX 3 – MX 5), and no pores, nor variable setae (gMX) on dorsal side; lacinia ( Fig. 27 ) without setae; galeomere without setae; palpomere 1 and 2 without setae, palpomere 3 with 2 minute apical setae, no pores.

Thorax. Prothorax: Figs. 28-29 . Notum ( Fig. 28 ) with 12 major “ancestral” setae (PR 2 – PR 4, PR 6 – PR 14) and numerous auxiliary setae (not labeled), and no pores on each side. Epimeron, episternum, and trochantin not defined. Prosternite ( Fig. 29 ) with a ring of auxiliary setae, gPS absent.

Mesothorax and metathorax: Figs. 28-29 . Mesonotum ( Fig. 28 ) with 9 “ancestral” setae (ME1 – ME2, ME8 – ME14), and no pores on each side. Mesepisternum ( Fig. 28 ) with 1 seta (PL1) and no pores. Trochantin and epimeron not defined. Sternum

( Fig. 29 ) with 9 setae (unlabeled) in a median rosette. Metanotum ( Fig. 28 ) with 5 “ancestral” setae (MT2, MT7 – MT9, MT12), and no pores on each side. Metepisternum ( Fig. 29 ) with 5 setae (unlabeled) and no pores. Trochantin and epimeron not defined. Sternum ( Fig. 29 ) with 14 setae (unlabeled) in a median rosette.

Abdomen. Figs. 30-34 . Tergite I ( Fig. 30 ) with 11 “ancestral” setae (TE1 – TE11) and 5 auxiliary setae (not labeled), and no pores each side.Tergites II – VIII as in Tergite 1 with numerous auxiliary setae. Sternum with numerous setiferous rosettes. Tergite IX, X and urogomphi ( Fig. 32 ), all with numerous setae in raised rosettes or on raised lobes, and no

pores. Epipleurites ( Fig. 33 ) with numerous setae and no pores. Hypopleurite not defined. Segment VII sternite ( Fig. 33 ) with numerous setae in rosettes and no pores. Segments VIII and IX with numerous setae (not in rosettes) each side and no pores. Segment X (PY) sternite ( Fig. 33 , 34) with numerous auxiliary setae in apical 2/3 rd, with no pores.

Legs. As in Fig. 35 ; reduced size and setation compared to instar I.

INSTAR III. Form. ( Fig. 35 ) Hypermetamorphic stage 3 instar.

Coloration. White; head capsule creamy-white with mouth parts slightly infuscated in part; mandibles piceous at tips.

Chaetotaxy. Head. ( Figs. 35 -37 ) Frontale ( Fig. 36 ) with 9 “ancestral” setae (FR1 – FR5, FR7 and FR9) and and no pores each side. Parietale ( Figs. 36, 37 ) with 5 “ancestral” setae (PA4 – PA8) and 3 pores (PAa – Pac) each side. Antenna ( Figs. 36, 37 ): antennomere 3 with 1 seta (unlabeled); antennomere 4 with 3 in an apical ring; the dome-shaped hyaline sensillum absent. Mandible ( Fig. 36 ) falciform without setae and pores. Labium ( Fig. 37 ): prementum with 1 seta (LA5) and no pores each side; labial palpomeres reduced and without vestiture. Maxilla ( Fig. 37 ): cardo with 1ventral seta (ca1); stipes with 5 “ancestral” setae ( MX 1 – MX 5), and no pores and no variable setae (gMX) on dorsal side; lacinia and galeomere absent; maxillary palpomeres reduced with palpomere 1 unisetose (pa10) and without other visible sensory features.

Thorax. Prothorax: Notum ( Figs. 38 – 40 ) with numerous long setae on front margin and numerous shorter setae posteriorly (not labeled), and no pores on each side. Parietal with 6 “ancestral” setae (PR 2 – PR 4, PR 6, PR 8, PR 14) and numerous auxiliary setae (not labeled), and no pores on each side. Epimeron ( Fig. 38 ) with 5 setae (EP3 – EP4, EP6, EP10 – EP11), and no pores on each side. Episternum and trochantin not defined. Prosternite ( Fig. 40 ) with numerous medial auxiliary setae some in a rosette, gPS absent.

Mesothorax and metathorax: Notum ( Figs. 38 , 39 ) with 2 long setae medially and 3 shorter setae nearby (not labeled), and no pores on each side. Episternum ( Fig. 38 ) with numerous stout setae and no pores. Epimeron and trochantin not defined. Sternum with rosette of setae medially ( Fig. 39 ).

Abdomen. Figs. 41 – 44 . Tergite I ( Fig. 41 ) with 2 stout setae medially and numerous shorter auxiliary setae in patches (not labeled), and no pores each side. Tergites

II – VIII as in Tergite 1. Tergite IX with 2 stout setae each side and numerous shorter setae nearby. Tergite X (PY) with numerous short apical setae and no pores. Epipleurite IX ( Fig. 44 ) with numerous long and stout setae on raised knob and no pores. Hypopleurite not defined. Segment VII and VIII sternites ( Fig. 44 ) with numerous setae on raised knobs in rosettes each side and no pores. Segment IX sternite ( Fig. 44 ) with subapical band of short setae each side and no pores. Segment X (PY) sternite ( Fig. 35 , 44 ) with numerous scattered short setae each side, no pores.

Legs. As in Fig. 35 ; reduced size and setation compared to instar I.

PUPA. Form. ( Fig. 45 ) Typical of carabid species. In addition, pygidium with fine short setae and dorsal surface with an array of small tubercules.

Notes on advancing an understanding of phylogenetic relationships. Much works still needs to be done in solving to infer the relationships between the Brachininae tribes Crepidogastrini and Brachinini and the subtribes Brachinina , Pheropsophina, and Masticina ( Erwin 1970). Here we have added larval traits that will, in part, add information toward a more robust phylogenetic analysis in the future. Immature stages of Crepidogastrini and Masticina are, as yet unknown, and we do not even know whether they are ectoparasitoids, or specialized predators. Likely, they are one or the other, but on what taxa? Larvae of Brachinus develop in 5 instars; they also have 6 eyespots (as in other carabids), whereas Pheropsophina larvae have 3 instars and at most a single eye-spot, usually none. First instar Brachinus have no egg burster and chew their way out of the egg ( Erwin 1967); Stenaptinus larvae possess a single-toothed egg burster; those of Pheropsopus have a triple-toothed egg burster. Pheropsophina larvae have pygidial hooks that aid them in attacking mole cricket egg clutches (Habu and Sadanga 1969), whereas Brachinus larvae do not. Larvae of Stenaptinus and Brachinus possess urogomphi whereas those of Pheropsophus do not.

Figures

Figure 1. Riverine beach habitat of P.aequinoctialis along the Río Madre de Dios watershed, Peru (Photo credit:T.L. Erwin).

Figure 2. Frequency of numbers of eggs laid daily by S. jessoensis females in February 1987 (Σ observations = 145 excluding records of zero).

Figure 3. Frequency of numbers of eggs laid daily by P. aequinoctialis females in February-April 1987 (Σ observations = 145 excluding records of zero).

Figure 4. Scanning Electron Micrograph of egg of S. jessoensis: a, complete egg; b, apical micropore; c, surface texture; d, microperforations.

Figure 5. Habitus (left lateral aspect) of S. jessoensis, first instar; legs not shown.

Figures 6-7. 6 – Head (dorsal aspect) of S. jessoensis, first instar; ventral mouthparts and left antenna not shown. 7- Head (ventral aspect) of S. jessoensis, first instar; mandibles and antennae not shown.

Figures 8-11. 8 – Th orax (dorsal aspect) of S. jessoensis, first instar; legs not shown. 9 – Thorax (ventral aspect) of S. jessoensis, first instar; legs not shown.10 – Abdominal terga I & II (dorsal aspect) of S. jessoensis, first instar. 11 – Abdominal sterna I & II (ventral aspect) of S. jessoensis, first instar.

Figure 15. Scanning Electron Micrograph of egg of P. aequinoctialis: a, complete egg; b, apical aspect showing polygonical relief; c, surface texture; d, microperforation distribution; e, microperforations.

Figure 16. Habitus (left lateral aspect) of P. aequinoctialis, first instar; legs not shown.

Figure 25. Legs (dorsal aspect, left side of thorax) of P. aequinoctialis, first instar.Top, anterior leg; middle, middle leg; bottom, posterior leg.

Figure 35. Habitus (left lateral aspect) of P. aequinoctialis, third instar; legs shown.

Figure 38. Head and prothorax (left lateral aspect) of P. aequinoctialis, third instar.

Figures 39-44. 39 – Th orax (dorsal aspect) of P. aequinoctialis, third instar; legs not shown. 40 – Thorax (ventral aspect) of P. aequinoctialis, third instar; legs not shown. 41 – Abdominal terga I & II (dorsal aspect) of P. aequinoctialis, third instar. 42 – Abdominal sterna I & II (ventral aspect) of P. aequinoctialis, third instar. 43 – Abdominal terga VII to X (dorsal aspect) of P. aequinoctialis, third instar. 44 – Abdominal sterna VII to X (ventral aspect) of P. aequinoctialis, third instar.

Figure 45. Pupa of P. aequinoctialis, dorsal (left), ventral (middle), and left (right) lateral aspects

Figures 23-24. 23 – Abdominal terga VII to X (dorsal aspect) of P. aequinoctialis, first instar. 24 – Abdominal sterna VII to X (ventral aspect) of P. aequinoctialis, first instar.

Figures 17-18. 17 Head (dorsal aspect) of P. aequinoctialis, first instar; ventral mouthparts and right antenna not shown. 18 Head (ventral aspect) of P. aequinoctialis, first instar; mandibles and antennae not shown.

Figures 19-22. 19 Thorax (dorsal aspect) of P. aequinoctialis, first instar; legs not shown. 20 Thorax (ventral aspect) of P. aequinoctialis, first instar; legs not shown. 21 Abdominal terga I & II (dorsal aspect) of P. aequinoctialis, first instar. 22 Abdominal sterna I & II (ventral aspect) of P. aequinoctialis, first instar.

Figures 26-27. 26 – Head (dorsal aspect) of P. aequinoctialis, second instar; ventral mouthparts not shown. 27 – Head (ventral aspect) of P. aequinoctialis, second instar; antennae not shown.

Figure 28-33. 28 – Th orax (dorsal aspect) of P.aequinoctialis, second instar; legs not shown. 29 – Thorax (ventral aspect) of P. aequinoctialis, second instar; legs not shown. 30 – Abdominal terga I & II (dorsal aspect) of P.aequinoctialis, second instar. 31 – Abdominal sterna I & II (ventral aspect) of P. aequinoctialis, second instar. 32 – Abdominal terga VII to X (dorsal aspect) of P. aequinoctialis, second instar. 33 – Abdominal sterna VII to X (ventral aspect) of P. aequinoctialis, second instar.

Figures 36-37. 36 – Head (dorsal aspect) of P.aequinoctialis, third instar; ventral mouthparts not shown. 37 – Head (ventral aspect) of P. aequinoctialis, third instar; antennae shown.