Preliminary analysis of a host shift: revision of the Neotropical species of Apocephalus, subgenus Mesophora (Diptera: Phoridae)

36 Pages·1996·27.6 MB·English

by  Brian V Brown

Preliminary Analysis of a Host Shift:
Revision of the Neotropical Species of
Apocephalus, Subgenus Mesophora
(Diptera: Phoridae)
Brian V. Brown1
CONTENTS
ABSTRACT 2
INTRODUCTION 2
METHODS
2
SYSTEMATICS 3
Phylogenetic Reconstruction 3
Monophyly of Subgenus Mesophora 3
Recognition of Subgenus Mesophora 3
Relationships within Subgenus Mesophora 3
Apocephalus borealis-group 7
Apocephalus wheeleri-group 15
Apocephalus Coquillett, 1901; Subgenus Mesophora Borgmeier, 1937 16
Apocephalus apivorus new species 16
Apocephalus atavus new species 17
Apocephalus adustus Brown, 1993 17
Apocephalus borealis-group 18
Apocephalus anfractus-subgroup 18
Apocephalus absentis Brown, 1993 18
Apocephalus bisetus Brown, 1993 19
Other Apocephalus borealis-group species 19
Apocephalus megalops new species 19
Apocephalus emphysemus new species 19
Apocephalus wheeleri-group .. 20
Apocephalus curtus-subgroup 20
Apocephalus lizanoi new species 20
Apocephalus curtus Brown, 1993 21
Apocephalus lemniscus new species 21
Apocephalus wheeleri-subgroup 22
Apocephalus niveus new species 22
Apocephalus antennatus-infragroup 23
Apocephalus antennatus Malloch, 1913 23
Apocephalus longistylus Brown, 1993 23
Apocephalus wheeleri-infragroup 23
Apocephalus mortifer Borgmeier, 1937 23
Apocephalus tritarsus Brown, 1993 23
Unplaced Species 23
Apocephalus micrepelis Brown, 1993 23
Apocephalus pilatus new species 23
Apocephalus crassus new species 24
Apocephalus prolixus new species 24
Apocephalus secundus new species 25
1. NaturalHistoryMuseumofLosAngelesCounty,900ExpositionBoulevard,LosAngeles,California,90007.E-mail:
[email protected].
Contributions in Science, Number462, pp. 1-36
Natural HistoryMuseum ofLos Angeles County, 1996
Apocephalus echinatus new species 25
Species Recognized but Not Named 26
Phorid Species 3251 26
Phorid Species 3223 26
Phorid Species 3246 27
.
Phorid Species 3247 27
Phorid Species 3250 27
Phorid Species 3252 28
Phorid Species 3253 29
IDENTIFICATION 29
Key to Males ofNeotropical Region Mesophora Species 29
Key to Females ofNeotropical Region Mesophora Species 31
EVOLUTION OF HOST SELECTION 32
ACKNOWLEDGMENTS 35
LITERATURE CITED 35
ABSTRACT. Twelve new species of Apocephalus, subgenus Mesophora, are described and named; an
additional six unassociated males and females are described but not named. The 12 new species are A.
apivorus, atavus, emphysemus, lemniscus, lizanoi, megalops, and niveus from Costa Rica and A. crassus,
echinatus, pilatus, prolixus, and secundus from the Dominican Republic. A. leptotarsus Brown is synon-
ymized with A. antennatus Malloch new synonymy. The previously unknown male ofA. absentisBrown
is described, as arethe previously unrecognized females ofA. adustus andA. curtus. Anewkeytospecies
of the Neotropical Region is given. The relatively most primitive species, A. apivorus and adustus, are
parasitoids of stingless bees, whereas A. tritarsus is a parasitoid of lampyrid beetles, like most otherMe-
sophora. The host shift within the subgenus Mesophora from ants to lampyrid beetles appears to have
been via parasitism ofstingless bees.
INTRODUCTION METHODS
In a group of flies that are remarkably similar in Methods and terms are similar to those used in my pre-
their life histories, species of the genus Apocepha- viimopuosrtraenvtisidoinfsfeorfentcheisisgrthoautpI(nBroowlonn,ge1r99r3e,po1r9t94obn).coOstnael
lus, subgenus Mesophora, represent a major enig- sector ratios. The point that these measurements are of
ma. Whereas all other species ofthis genus are par- little use in identification, becausetheyvarysomuch,has
asitoidsofants (Hymenoptera: Formicidae),species been adequately made (Disney, 1980). An overwhelming
ofMesophora attack beetles, wasps, bees, and spi- reliance on them by previous workers is a thing of the
ders (Brown, 1993). The reasons for this host shift past.
are unknown; other genera hypothesized to be re- Another change is that I no longer use potassium hy-
droxide to clear specimens. Following other dipterists
l(aBtreodwnt,o1A99p2o)c,epshoaaltutsackailnsgo tahreeneanwt-hpoasrtassisteoeimdss t(hCautmimsimnugc,h19s9af2e)r,fIornospwecuismeenlsac.tic acid as an alternative
to represent a newly derived behavioral character For brevity, species names are cited as follows: Apo-
(Brown, 1993). Studyofthisphenomenonisanim- cephalusmortiferorA. mortifer, ratherthanApocephalus
portant reason for this revision. (Mesophora) mortiferand A. (M.) mortifer.
Although only a short period oftime has passed Geographical coordinates are quoted as decimal de-
since the first revision of Mesophora (Brown, grees, ratherthan degrees, minutes, and seconds.
1993),alreadyasignificantamountofnewmaterial In addition to the usual insect labels recording locality
information,specimenswerelabelledwithbarcodedinsect
has accumulated. Previously, I dealtwith one small labels (Thompson, 1994) anddatawererecordedinada-
subgroup (Brown, 1994b) and some new life his- tabase. All barcoded labels begin with the abbreviation
tory information (Brown, 1994a), but in general “LACM ENT,” indicating that the Natural History Mu-
there still seems to be an almost unlimited number seum of Los Angeles County is the institution where the
ofnewspeciesto discover. Largecollectionsstillare data are stored. To make later recognition of holotypes
available from only two countries, Costa Rica and easier, I list their individual barcode number in square
brackets.
the Dominican Republic, so it seems likely that as Specimens were deposited in the followingcollections:
other sites are surveyed still more species and re-
markable life histories will be uncovered. CMNH Section of Invertebrate Zoology, Carnegie Mu-
In this paper, I describe newly discovered species sPietutmsboufrgNha,turPaAl H1i5s2to1r3y-,44048000, FUo.rSb.eAs.Av(eCn.uWe.,
and life histories, reviewing previously described Young)
taxa only when significant new information is INBIO Instituto Nacional de Biodiversidad, A.P.
available. The key to species, however, includes all 22-3100, Santo Domingo, Heredia, Costa Rica
species described previously (Brown, 1993, 1994b). (M. Zumbado)
2 Contributionsin Science, Number 462 Brown: NeotropicalApocephalus, SubgenusMesophora
LACM Entomology Section, Natural History Museum 2) orus and the rest of Mesophora (excluding A.
of Los Angeles County, 900 Exposition Boule- atavus and adustus
vard, Los Angeles, CA 90007, U.S.A. (B.V. Ovipositor notched).(Brown, 1993, fig. 51, n)
Brown)
MCZ Museum of Comparative Zoology, Harvard (plesiomorphic: ovipositor not notched)
MA This character reverses later in the subgenus.
University, Cambridge, 02138, U.S.A. (on
indefiniteloan to B.V. Brown)
MICR Museo de Insectos, Universidad de Costa Rica, Recognition of Subgenus Mesophora
San Pedro, SanJose, Costa Rica (P.S. Hanson)
USNM United States National Museum, Smithsonian Because of the reversals of characters in the sub-
Institution, Washington, DC20560, U.S.A. (on genus, identification of an Apocephalus species as
indefinite loan to B.V. Brown) Mesophora is now complicated. The followingkey
As previously, I name species only based on malespec- will allow recognition of all species:
imens; an exception is the Apocephalus anfractus-sub- 1 Male 2
group, which was based on females. Unfortunately, this Female 5
means that many forms known from one sex or another
onlycannot be formallydealtwithatthistime,especially 2 Flagellomere 1 greatly enlarged (Figs. 3-5);
the now known, but unassigned, males of A. anfractus- lower and usually upper fronto-orbitalsetae
subgroup taxa. Unnamed Costa Rican species are de- absent subgenus Mesophora
scribedhereintofacilitatetheirrecognitioninCostaRica’s - Flagellomere 1 small, round; fronto-orbital
ongoing biodiversity inventories; they are referred to by setae present (Fig. 1) 3
theirPhoridSpeciesNumberinmyphoridnamesdatabase 3 Wing vein CuAj short, not reaching wing
(e.g., Phorid species 3143). To make later recognition of margin
thesespecimenseasier,Ilisttheirindividualbarcodenum- .... A. Mesophora apivorus new species
ber in square brackets intheMaterialExaminedsections. - Wing vein( CuAj reach)ing wing margin 4
. .
4 Anteroventral row of setulae on hind basi-
SYSTEMATICS
tarsus enlarged basally (similar to Fig. 63);
PHYLOGENETIC RECONSTRUCTION flagellomere 1 pyriform; halter dark brown
A. Mesophora atavus new species
( )
There are numerous species known from a single - Anteroventral row of setulae on hind basi-
sex only. The lack of phylogenetic information tarsus not noticeably enlarged; other char-
from the missing sexes makes phylogeneticanalysis acters various .... subgenusApocephalus
using a computer program impossible; huge num- 5 Abdominal glands near segment 5 dark in
bers of alternative trees are generated as the pro- color (Brown, 1993, fig. 45, g); if not, ovi-
gram attempts to analyze all possibilities of the positor with ventral notch apically (Brown,
missing character states. For that reason, the fol- 1993, fig. 51, n) ... subgenus Mesophora
lowing analysis is based only on taxa known from - Abdominal glands white, invisible incleared
b1)oth sexes, including those from the Nearctic Re- specimens; ovipositor lacking ventral notch
gion. Also excluded is the new species A. atavus, 6
for reasons stated in the discussion of the A. bo- 6 Lower fronto-orbital setae absent; in some
realis-group. species upper fronto-orbital setae also ab-
sent subgenus Mesophora
Monophyly of Subgenus Mesophora - Fronto-orbital setae present
subgenusApocephalus
The monophyly of subgenus Mesophora is no lon-
ger supported by all of the same character states I Relationships within Subgenus Mesophora
proposed earlier (Brown, 1993). The discovery of
A. apivorusreducesthe numberofpossiblesynapo- Within Mesophora, I propose the following hy-
morphies ofthe group to the two listed below. The pothesized synapomorphic characters:
larval synapomorphies I proposed earlier are still
speculative. The larva of A. apivorus is similar to 3) Male flagellomere 1 enlarged, flattened (ple-
that of other Mesophora, and divergent from the siomorphic: flagellomere 1 round)
only describedlarva ofanApocephalus Apocepha- 4) Stylet with lateral barbs (plesiomorphic: barbs
{
lus species (Brown and Feener, 1991), butourlack absent)
of )knowledge about the larvae of outgroup taxa 5) Lower fronto-orbital seta of male absent (ple-
makes proposing larval synapomorphies of Meso- siomorphic: present)
phora premature. 6) Upper fronto-orbital seta of male absent (ple-
siomorphic: present)
Female with dark glands (plesiomorphic: ab- 7) Lower fronto-orbital seta of female 1) slightly
dominal glands white) displaced medially, 2) in line with interfrontal
Because dark glands are absent from A. ata- setae (Fig. 10) (plesiomorphic: lowerfronto-or-
vusandthenextmostprimitivespecies,A.adus- bital seta close to eye)
tus, it is also equally parsimonious to propose 8) Ovipositor cylindrical (plesiomorphic: ovipos-
that the dark glands arose separatelyinA. apiv- itor flat)
Contributionsin Science,Number462 Brown: NeotropicalApocephalus, SubgenusMesophora 3
9)
Dorsal apex of ovipositor rounded (plesio- to-orbital seta is absent from females of species
morphic: apex pointed) 3223 (Fig. 12), and both the upper and lower
10) Ventral apex of ovipositor rounded (plesio- fronto-orbital setae are absent from females of
morphic: apex pointed) species 3251 (Fig. 11).
11) Anteroventralrowofsetulaeofhindtarsomere b) Series of long, thick ventral setae on left side of
with at least basal setulae enlarged (Figs. 63- epandrium.
65) (plesiomorphic: setulae all short, subequal) Study of additional species has shown that
12) Anteroventralrowofsetulaeofhindtarsomere “thick” and “thin” epandrial setae grade into
sinuate (Fig. 65) (plesiomorphic: row straight) each other. The distinction can no longer be
13) Ventral setae of female abdominal segment 6 maintained.
1) reduced (thin, but still long), 2) greatly re- c) Right side ofepandrium with prominent,darkly
duced (short, thin), 3) absent (plesiomorphic: sclerotized longitudinal ridge.
ventral setae large, thick, prominent) This character is found widely, including in
14) Venter of mid tarsomere 2 with at least one the newly described, relativelyprimitiveA. apiv-
extra setula (plesiomorphic: with only one set- orus.
ula)
15) Flagellomere 1 of male abruptly narrowed at Based oncharacters 1-28 listedabove,Ianalyzed
base (Fig. 9) (plesiomorphic: flagellomere 1 a character matrix (Table 1) using HENNIG86.
more gradually narrowed) Characters were polarized with reference to the
16) Anterior margin of ovipositor narrowly pro- outgroup taxa Pseudacteon Coquillett and Neo-
duced in an anterior strip (Brown, 1994b, fig. dobrniphora Malloch; species of these genera have
5A) (plesiomorphic: ovipositor anteriorly the synapomorphic character of pointed horns on
rounded) the larval spiracle in common with Apocephalus
17) Apex of male cercus truncate (plesiomorphic: species (as in Brown, 1993, fig. 99s). Allcharacters
apex ofcercus elongate) were equally weighted, and multistate characters
18) Ovipositor darkly sclerotized over entire sur- unordered. This produced sixequallyparsimonious
face (plesiomorphic: dark sclerotization con- trees (length 49, ci 67, ri 81). The number oftrees
fined to margin of ovipositor) was unaffected by successive approximation
19) Surstylus with three or fewer setulae (plesio- weighting.
morphic: surstylus with many setulae) Of these six trees, three treated character 25,
20) Palpus of male enlarged, with few short, stub- state 2, as a synapomorphy of A. unitarsus and
by setulae (plesiomorphic: palpus small, with wheeleri. However, this state is also found in a rel-
normal, pointed setulae) atively primitive member ofthis group, A. hansoni
21) Venter of female abdomen with distinctive Brown, not included in this analysis. Because an-
combs of setulae (Figs. 66-67) (plesiomorphic: othercharacter supports the monophylyofagroup
abdomen without combs of setulae) not including A. hansoni, character 25, state 2, is
22) Female stylet distinctive, with medial sclerite a primitive character in reference to A. unitarsus
on venter (Figs. 60-61) and A. wheeleri and cannot group these two spe-
23) Male abdominal segment 6 with dark ventral cies.
setae (Fig. 70) (plesiomorphic: setae absent) The three remaining trees differonly bydifferent
24) Epandrium extremely short (Figs. 20-22) (ple- assignmentsofstatesofcharacter 13 atvariousbas-
siomorphic: epandrium longer) al nodes ofthe cladogram. In tree 1 (Lig. 71) there
25) Surstylus with 1) single carina, 2) short multi- is a branch including the species A. grandiflavus-
ple carinae, 3) long, complete carina (plesio- A. wheeleri. This branchis resolved byanarbitrary
morphic: carinae absent) assignment of the state of character 13 as 0, 1, or
26) Mid tarsomere 1 of male enlarged (plesio- 3 and allows two furthermonoph—yleticgroups:one
morphic: tarsomeres slender) is composed of A. grandiflavus A. truncaticercus
27) Left side of epandrium with distinct ventral and is supported bycharacter 13, state 3; the other
ridge (plesiomorphic: ridge absent) is A. longistylus-A. wheeleri and is supported by
28) Right surstylus elongate (plesiomorphic: sur- character 13, state 1. Tree 2 differs by depicting a
stylus short) sister-group relationship betweenA. niveus and the
rmleoygnAagprenrdreuevcdmio.boneusArsidoaleifnrsaithlnyyogspfiotstthhhe(eemBsmri,aozsweandpn,hsdyy1lno9tgha9eep3n)oermtehoiaarcsdpaolhntlisoyesbfuoseferfrduinolsom,- o—su3tlt>aahhtt3eaee)rs,1taa.shnpnaTethcauiisncesrshseau,tsrmraopweclethtviieieoscrdnhsp1in3moaoirltleiyasmtrauoondrtmiodeyteeoriidnnenedctblhtyui(hsadasicatnhn0gaawlroA—ya.usc»iltns1ed.irv—Tsetru1»ies3p2e,,-
is given below: the A. truncaticercus infragroup (see below), and
a) Lower fronto-orbital seta absent from female. A. longistylus-wheeleri. The consensus tree of the
Lronto-orbital setae are extremely variable six equally parsimonious trees is given in Lig. 71.
throughout Mesophora. Lor instance, in the A. All of the significant differences among these
borealis-group, all frontal setae are present in trees are because of character 13. I prefer tree 2
femalesofspecies 3246 (Lig. 13),thelowerfron- because it has the most modest assumption about
4 Contributionsin Science, Number462 Brown: NeotropicalApocephalus, SubgenusMesophora
— —
Figures 1—6. Heads. Abbreviations: 1 f-o lowerfronto-orbitalseta; u f-o upper fronto-orbitalseta.
Contributionsin Science, Number462 Brown: NeotropicalApocephalus, SubgenusMesophora 5
—
Figures 7-12. Heads. Abbreviation: 1 f-o lower fronto-orbitalseta.
6 Contributions in Science, Number462 Brown: NeotropicalApocephalus, SubgenusMesophora
15. ?A. antennatus 16. SA. longistylus 17. $Phoridspecies 3136
Figures 13-17. Heads.
this character: that the reduction of abdominal se- The relationships of the other species of the A.
taeis synapomorphic,regardlessoflater, furtherre- borealis group are less clear. Based on the enlarged
ductions. Thus, it can define a monophyletic group costa of males, A. borealis Brues and A. emphyse-
that does not include A. niveus. mus are probably sister taxa. Species 3223 and
Based on this analysis, the following informal 3246 are also clearly related to A. borealis based
groups can be recognized. on the broad apex of the ovipositor, and one of
Apocephalus borealis-group.Thisgroup is based these two species probably is the female ofA. em-
on the presence of enlarged ventral setulae on tar- physemas.
somere 1 ofthe hind leg. Withinthisgroup aretwo The remaining taxa are A. megalops, species
subdivisions, one of which is the A. anfractus-sub- 3251, species 3247, and possibly A. atavus. The
group (represented by A. absentis in this analysis). first three species are relatively similar, althoughA.
This assemblage of species is well defined by the megalops and species 3247 have barbed stylets and
presence of a sinuate line of setulae on hind tarso- might be part ofa group including A. borealis and
mere 1. The relationships of the A. anfractus-sub- relatives. This character, however, has occurred
group were discussed previously (Brown, 1993). more than once in the subgenus Mesophora, and
Contributions in Science, Number462 Brown: NeotropicalApocephalus, SubgenusMesophora 7
Figures 18-25. Male terminalia, right lateral and left lateral.
8 Contributions in Science, Number462 Brown: NeotropicalApocephalus, SubgenusMesopbora
26 27
. .
Figures26-33. Maleterminalia, right lateral and leftlateral.
Contributionsin Science, Number462 Brown: NeotropicalApocephalus, SubgenusMesophoraI9
35
.
Figures 34-41. Male terminalia, right lateral and left lateral.
10 Contributionsin Science, Number462 Brown: NeotropicalApocephalus, SubgenusMesophora