Alan W. Hook and Robert W. Matthews.
Nesting Biology of Oxybelus sericeus with a Discussion of Nest Guarding by Male Sphecid Wasps (Hymenoptera).
Psyche 87(1-2):21-37, 1980.

This article at Hindawi Publishing: https://doi.org/10.1155/1980/14621
CEC's scan of this article: http://psyche.entclub.org/pdf/87/87-021.pdf, 3188K
This landing page: http://psyche.entclub.org/87/87-021.html

The following unprocessed text is extracted automatically from the PDF file, and is likely to be both incomplete and full of errors. Please consult the PDF file for the complete article.

NESTING BIOLOGY OF OXYBELUS SERICEUS
WITH A DISCUSSION OF NEST GUARDING BY MALE SPHECID WASPS (HYMENOPTERA)
BY ALLAN W. Hook1 AND ROBERT W. MATTHEWS Department of Entomology
University of Georgia
INTRODUCTION
Among sphecid wasps males are regularly associated with nesting females only in a few species. A review of territorial behavior in male sphecids (Alcock, 1975) has shown that such behavior is typically associated with obtaining copulations. Only rarely do males actively participate in nest maintenance or prey manipulation. Species of Oxybelus digger wasps show an unusual diversity of male behavioral adaptations. Several species display male nest guarding behavior, that is, a male defends a territory at sites of active nests and attempts to mate with the nesting female (Peckham et al., 1973; Peckham, 1977). Females exhibit an unusual prey carriage (impalement on the sting), and provision nests in exposed substrate with paralyzed Diptera.
Oxybelus sericeus is distributed throughout the United States and into Mexico (Bohart and Schlinger, 1957) and has been studied briefly by Bohart and Marsh (1960), who reported nest guarding. Here we present results of a two year study of the biology and behavior of 0. sericeus in Georgia and discuss the phenomenon of nest guarding in sphecid wasps.
Observations were conducted during 5 August to 15 September 1977 and 12 May to 12 June, 7 to 10 September, 7 to 9 October 1978 on St. Catherine's Island, 30 miles south of Savannah, Georgia at five separate study sites. Three beach sites were used primarily in 1977. The sparse dune vegetation consisted primarily of sandspur (Cenchrus sp.) navelwort (Hydroctyl bonariensis Lam), and Croton punctatus Jacq. Air temperatures ranged between 32O and 40å C during May to present address: Department of Zoology and Entomology, Colorado State State University, FortCollins, Colorado 80523. Manuscript received by the editor June 6, 1980.



================================================================================

22 Psyche [vo~. 87
September. In 1978 the Boiler site (see Fig. 5 in Matthews et al., 1979) was mainly used. Observations were made from 0800 to 1800 on most days. Notes were taken in the field, supplemented with motion pictures of mating. Cell contents from nest excavations were transferred to sand-filled tins for rearing at room temperatures. Male observations used distinctively marked individuals and were mostly carried out at the Boiler site.
Activity Periods and Development.
Oxybelus sericeus is a multi
voltine species that first emerged in May and continued to nest into October. Rearing data revealed that both sexes required about 26 days (25 to 27 males, n=7; 26 to 27 females, n=5) to develop from hatched egg to an emerged adult. Males appeared first in the morning (0830 to 0930) about 15 to 30 minutes before females. After females ceased provisioning males dug sleeping burrows between 1700 to 1900, 2 to 3 cm deep in the nest area.
Nest Construction and Architecture. Nests were typically dug in exposed sand, but some females constructed nests under washed-up Spartina or shells. Nest structure is essentially the same as that of 0. subulatus Robertson (Peckham et al., 1973). The only difference was the absence of a tumulus about 0. subulatus nests because of its carrier-type digging behavior. Nest digging in 0. sericeus was initiated by biting the surface and pushing back the loosened sand with the legs. As the burrow deepened sand was apparently gathered between the venter and hind legs and pushed up the vertical burrow, forming a tumulus. Tumuli were leveled after digging was completed and ranged 2 to 5 cm in diameter. Leveling consisted of females repeatedly raking sand 1 to 3 cm away in all directions from the perimeter of the entrance, and returning to the entrance. In multicellular nests filler sand for the completed cell was obtained from the nest side burrow and cell excavation. Excess sand was brought to the surface, forming a tumulus which was subsequently leveled. After leveling, females began "orientation" flights, meandering paths 1 to 5 cm above the nest area, which lasted 2 to 5 min. and covered 1m2 surrounding the nest.
Cell depths averaged 7.9 cm (3.5 to 15, n= 182). Cell dimensions varied, averaging 16.8 mm (8 to 24, n=97) long and 5.6 mm (4 to 7, n=99) wide. An average of 1.7 cells was present per nest (range, 55%



================================================================================

19801 Hook & Matthews - Biology of Oxebelus 23 had 1 cell and 0.9% had 6 cells). Final closure is similar to that reported for other Oxybelus (Peckham et al., 1973) and this process took 35.5 min (15 to 45, n=15). Ten nests made by one female had from 1 to 6 cells per nest. Females often constructed series of nests in localized areas (ave. distance between 9 nests by 1 marked female was 10.9 cm, range 1.5 to 26 cm). One female was found nesting 400 m across salt marsh from its original nesting area. Intraspecific nest usurpation was observed once.
Provisioning and Prey Carriage.
The mean duration between
provisioning trips was 7.2 min. (1 to 140, n= 163) with interruptions for mating included. Provisioning was most frequent between 1000 to 1700. Once a cell was full the female plugged the entrance from within the nest for oviposition and prey arrangement. Wasps provisioned up to three cells per day.
Ninety-six percent of the prey from 149 completed cells consisted of three species of Diptera (Table 1). Cells averaged 7 flies per cell (3 to 14, n= 152); prey arrangement and egg placement may be classified as Crabro-style (Iwata, 1942).
Oxybelus sericeus females transported prey from salt marsh to the nest area using pedal type 1 carriage (Evans, l962), using their legs to grasp the prey. Once alighted near the nest (5-1004- cm from the nest, termed the "initial landing site" in Peckham ef al., 1973) a female took a few seconds to face in the general nest direction. At this point she either impaled the prey on the sting (Fig. 1) or continued to carry the prey pedally as she crawled and/ or flew the remaining distance to the nest. Some females only used pedal carriage as they transported prey entirely in flight, omitted the initial landing site and dropped into the open entrance (only very small flies were carried in this manner, see below).
Most Oxybelus transport prey from the point of capture to the nest area using pedal carriage (i.e. bipunctatus and uniglumis, Peckham and Hook, in press). Prey is then impaled and the nest entered. Oxybelus sericeus differs from the others in that females may enter the nest using either pedal or impalement carriage. ~urobservations suggest that prey size influences the type of prey carriage used. Large, bulky prey normally elicited impalement carriage while small, less cumbersome prey were carried pedally. Prey weight corroborates this (Table 1). Ephydrids and some otitids averaged the least in weight and were rarely observed impaled, while dolichopodids averaged the heaviest and were usually impa1e.d. Impalement carriage allows large



================================================================================

24 Psyche [vol. 87
prey to be dragged, attached by the sting, enabling more efficient ground transport (the sting is impaled through a forecoxial corium, Steiner, 1979). Other factors may elicit impalement carriage. After copulation many females impaled (whether the prey was held pedally or impaled before copulation) and then entered their nests. Impaling under these conditions may speed up prey transport, minimizing further interruptions by males.
Mortality. Cleptoparasitic miltogrammine flies (Sarcophagidae) were regularly present at all sites, with the genera Senotainia and Metopla predominant. Mihogrammine maggots were found in 14.5% fn=75) of the cells excavated at the beach sites, but the Boiler site had only 3.7% (n=107), Semamia flies were attracted to males, females and mating pairs. Flies often hovered or perched behind copulating pairs though larviposition was not observed. Most flies followed the male after separation, enabling the female to provision safely.
One beach site had 13.5% cell mortality due to the ant Solenopsis pergundi Forel (Forrnicidae). This ant appeared to rob cells while Figure 1. A female 0. seticeus with a fly (Chaetopsis aema) impaled on her sting. Nest entrance is at left.




================================================================================

19801 Hook & Matthews - Biology of Oxebelus 25 Table 1. Prey weights for most abundant prey captured by Oxybelus sericeus and a summary of 903 prey records from St. Catherine's Island, Georgia. Weights are from frozen and subsequently thawed prey and are presumably slightly less than fresh weight due to dehydration.
Number
recorded Average
from all weight Sample
Species nests % (mg) Range size
OTITIDAE
Chaetopsis apicalis Johnson 209
Chaetopsis aenea (Wiedemann) 482
DOLICHOPODIDAE
Nanomyina litorea Robinson 184
The remaining 4% of the
prey consisted of:
DOLICHOPODIDAE
Paraclius sp. ( 1)
Paraclius hybridus Melander (2)
Paraclius filifer Aldrich (1)
Thinophilis sp. (1)
Thinophilis frontalis Van Duzee (5)
Pelastoneurus sp. (2)
Hypocharassus gladiator Mik (4)
Hypocharassus pruinosus (Wheeler) (2)
EPHYDRIDAE
Notiphila bispinosa Cresson (1)
Lipochaeta solossonae Cresson (1)
Polytrichophora conciliata Cresson (1)
Cirrula fuscifemur (Steyskal) (7)
tunneling below the surface. On three occasions, Conomyrma ants discovered active nests at the Boiler site and removed prey after recruitment of additional workers. Conomyrma ants were able to locate nests even after final closure. When excavating a completed nest, workers removed sand from the burrow until a stocked cell was reached. Mold accounted for 36% (~33) cell mortality at the Boiler site (sometimes high tides covered this site). Male Reproductive Strategies. Once a female began to nest, a male became closely associated with that nest as long as the female actively provisioned. Males perched near the entrance, either on the sand or a raised object (Fig. 2). Periodically the male changed positions, confining its activity to within 0.5 m of the nest. Guarding males often entered nests, particularly if females were late in returning, and sometimes stationed themselves head-out in the entrance, a guarding position typically used by 0. subulatus (Peckham, 1977 and pers. obs.). Territories encompassed an area approximately 1 m in diameter surrounding the nest entrance. Males chased all



================================================================================

26 Psyche [VOL 87
Figure 2.
A guarding male of 0. sericeus perched on a nest marker nait adjacent to an active nest.
intruding insects, especially rival males, and permitted only females to approach. Each time the female returned to or left the nest the guarding male attempted to mount. During copulation, the mounted male faced the same direction as the female, and used his middle legs to grasp the female's wings. The male's front legs were drawn in with the tarsi touching the female's pronoturn and the hind legs helping to support her gaster (Fig. 3). During copulation males alternate between biting the female's vertex and cervical region and antennating her antennae or frons. Some males were observed to copulate over twenty times per day, with a gradual decline in the copulation duration from about 2 min. to about 10 sec. After a female completed provisioning and plugged her entrance from within, the guarding male tended to patrol further from the nest, returning to inspect it intermittently. Such males usually took up defense of any unguarded nests they could locate. Presence of the male was not a prerequisite for provisioning; females nested whether or not a male guarded their nest.
Alternative to guarding of active nests we identified three other apparent male strategies: patrolling, guarding of the initial landing



================================================================================

1980) Hook & Matthews - Biology of Oxebelus 27 Figure 3. Copulation in 0, sericeus. The male is dorsal and grasps the female's wings with his middle legs while antennating her frons. The female's prey (Nanomyina liiorea) has been temporarily dropped to permit copulation. site and guarding lost prey. Patrolling consisted of cruising low (5 cm above ground) throughout the nest area without associating with particular nests. Males commonly used this behavior when searching for active nests to guard or exposed females. At times females provisioned infrequently, causing the majority of males to adopt the patrolling strategy. Guarding the initial landing site was possible because, as mentioned, preyladen females typically land away from the nest and then proceed to enter. On five occasions a male ceased nest guarding and instead took up defense of a territory about the initial landing site. Two conditions seemed prerequisite to this strategy: first, intense male competition for the nest territory; second, a propensity by the female to land repeatedly in the same area prior to entry. On ten occasions prey were abandoned by females when intensively interfered with by one or more males. When this occurred, males perched next to the prey, chased off intruding males and copulated with the female if she returned. Male-Male Competition.
It became apparent during the 1977
season that there was considerable individual variation in the number



================================================================================

28 Psyche [vo~. 87
of copulations obtained and that individual males were not limited to a single mating strategy. At the Boiler site we followed interactions between marked individuals daily for 22 days (15 May to 5 June). Of 51 males marked, 13 were observed an average of 7.5 days (5 to 13), 29 for 1 to 3 days and 9 were marked the last three days of the study. In addition to clarifying male mating strategies these data revealed that individual males differed greatly in their success in acquiring and defending nest territories.
Usually 5 to 12 males actively competed for territories and matings each day. Though the composition of males changed daily as new wasps emerged and marked ones disappeared, three males dominated our data. These "dominant" males won most encounters and thus were rarely forced to abandon a nest territory when challenged. Moreover, the "dominant" males quickly abandoned inactive nests and patrolled until they located an unguarded or (more likely) a guarded nest. Violent, aggressive interactions (Fig. 4) occurred between nearly equal size males competing for the same nest. An intruding male flew directly at the guard, and a fierce grappling match resulted, lasting from several seconds to over one minute. Often a series of grappling matches took place before one male retreated. "Dominant" males frequently usurped nest territories from other guarding males; one male usurped 15 territories in four days. Females displayed no obvious behavioral change when new males took over their nest territory. We believe that the isolation and relatively small size of the Boiler site area (7.6 X 2.4 m) enabled individual males to establish and maintain their dominance. One male won all encounters over a seven-day period and another male was completely dominant over a different four-day period. Female Receptivity.
Upon eclosion females were sexually recep- tive, allowing males to copulate for 2 to 3 minutes (ii~2.5, n=4), after which males dismounted. When mounted a female submitted quickly by raising her gaster, allowing copulation. Newly emerged females required a few days to develop mature eggs (dissections of newly eclosed wasps revealed small, clear eggs beginning to develop in the ovarioles). These females spent considerable time investigating the nesting area and were therefore easy targets for patrolling males. Once nesting began, females tended to avoid males when digging or provisioning. When intercepted, females varied in their response; some allowed a male to mate on most trips to the nest without



================================================================================

19801 Hook & Matthews - Biology of Oxebelus 29 Figure 4. A pair of 0. sericew males grappling to determine territory owncnihip. struggling, while others more strongly resisted male advances. Resistance consisted of bending the ester down and pygidium forwards, or dragging the mounted male and prey towards the entrance. Females appeared to initiate the termination of copulation by struggling, thereby inducing the male to dismount, although persistent males at times ignored such signals. Provisioning females mainly interacted with guarding males, but sometimes they were mounted by as many as four different males between the initial landing site and their burrow. Rarely a female dragged a mounted male and prey to the nest entrance, and squeezed past him into the burrow without permitting copulation. More commonly, male and prey were too cumbersome to transport (especially if over 50 cm from the nest); in this situation prey-laden females more readily submitted.




================================================================================

30 Psyche [VOI. 87
The most efficient strategy for 0. sericeus females appears to be to allow males to copulate, thereby minimizing the total energy and time spent in the interaction. The size of the nest area, density of nests, and the operational sex ratio probably greatly influence the quantity and intensity of male-female interactions. In order to better understand possible selective forces acting to bring about nest guarding in Oxybelus, comparison will be made with other nest guarding sphecids (Table 2). Wasps that have males associated with the parental nest (e.g. Microstigmus, Philanthus and Cerceris) are excluded here, but twig, cavity and mud nesters are included in Table 2 mainly to suggest that such interesting wasps deserve further study. Males in some species cue in on provisioning females. These males patrol and also perch next to active nests, though not associating with any particular nest. For this to evolve requires that females remain receptive throughout the nesting cycle. For a male the advantage would be in the increased probability of his sperm fertilizing the egg, assuming sperm precedence which is well documented in other insects (see Lefevre and Jonsson, 1962; Boorman and Parker, 1976; Smith, 1979). Gillaspy (1962) found males of Sphex trepanecus Saussure to cue in on provisioning females. When a prey-laden female approached her nest a male would appear and copulation occurred near the nest. The crabronine genus Lindenius commonly has males searching and entering nest entrances and Miller and Kurczewski (1 973) hypothesized that such "nest searching" behavior may help reduce cleptoparasitism (by miltogrammine flies and chrysidid wasps) in dense aggregations. Oxybelus emarginatus normally has males patrolling nest areas but Krombein (1964) once found males in Florida not only patrolling and perching but also mounting and copulating with provisioning females. One of us (AWH) recently briefly observed the same behavior in 0. emarginatus near Mission, Texas, only no copulations were observed. This ability to cue in on provisioning females probably developed early in the evolution of nest guarding. The transition from the ability to intercept provisioning females to establishment of territories in the nesting area seems a logical step. In Sphex cognatus Smith (Ribi and Ribi, 1980) and Tachysphex species (Kurczewski, 1966) males are known to maintain territorial stations in nesting areas and copulate with nesting females. In several other species male territories always include at least one female nest. These



================================================================================

19801 Hook & Matthews - Biology of Oxebelus 31 include Oxybelus subulatus (Peckham, 1977), Stizus (Megastizus) texanus Cresson (Gillaspy, unpubl.) and Tachytes distinctus Smith (Lin, 1963; Lin and Michener, 1972). Stizus texanus nested near Matomoros, Mexico and males defended nest territories, copulating with provisioning females. Tachytes distinctus defended nest territories but did not attempt to mate with provisioning females. Research on Trypargilum suggests that male guarding helps reduce cleptoparasitism and supersedure by other wasps and bees (Krombein, 1980). Males may also assist in nesting activities and females of at least one species will not provision unless a guard is present (Coville and Coville, 1980).
Peckham (1977) provides quantitative data on the effect of male 0. subulatus in reducing miltogrammine cleptoparasitism. Unguarded nests had 33% (examined 85 cells) cleptoparasitism while guarded nests had only 18%(n=84). "Thus the presence of the male appears to have significantly reduced miltogrammine cleptoparasitism." The low rate of cleptoparasitism in 0. sericeus at the Boiler site can be taken as indirect evidence that guards in this species reduce cleptoparasitism.
Earlier stages in the evolution of nest guarding as found in Oxybelus sericeus may be found in other Oxybelus. Several Oxybelus (bipunctatus, subcornutus Cockerell, emarginatus, Peckham et al., 1973 and pers. obs.; decorosus, uniglumis, Peckham and Hook, in press) fit this pattern whereby males patrol the nest area, indiscrimi- nantly chasing nearby moving insects. Peckham et al. (1973) found only 6% fly cleptoparasitism in an aggregation of 0. bipunctatus, and attributed this low figure partially to male harassment of miltogram- mine flies.
In summary, we suggest the following scenerio for the evolution of nest guarding in sphecid wasps. Initially males cue in on females who are actively provisioning nests and who remain continuously receptive to copulation attempts. Under certain ecological conditions the benefits resulting from defense of an area (territory) within a nest aggregation will exceed the costs to males. Sperm precedence may be an important factor in this context, if it occurs, for the last male to inseminate a female prior to oviposition will have increased fitness relative to other males. An incidental but important effect of the male's presence and activity is to reduce levels of cleptoparasitism (and perhaps supercedure) thereby improving a female's nesting success relative to females inseminated by non-territorial males. It



================================================================================

Table 2.
A compilation of records of male involvement in nesting in sphecid wasps arranged systematically following Bohart and Menke (1976).
Subfamily, tribe Species
Sphecinae
Sceliphronini Dynatus nigripes
Trigonopsis cameronii
Sphecini Sphex trepanecus
Sphex cognatus
Pemphredoninae
Pemphredonini Diodontus virginianus
Larrinae
Larrini Tachytes distinctus
Tachytes auricomans
Tachysphex apicalis
Trypoxylonini Pison strandi
Trypoxylon fabricator
Trypargilum collinum
rubrocinctum
Trypargilum striatum
Q attempts
(5 associates to mate w/
wlindividual Q at or
nest near nest
Yes no?
(5 deters Q assists
clepto- in nesting
parasites activities Source
-
no Kimsey, 1978
Yes no Eberhard, 1974
-
no Gillaspy, 1962
-
no Ribi & Ribi, 1979
-
no Krombein, 1958
- no Lin, 1963; Lin
and Michener, 1972
- no Hook, unpublished
- no Kurczewski, 1966
-
-
Masuda, 1939;
Tsuneki, 1970
- - Rau, 1933
Yes yes Peckham & Peckham,
1898; Paetzel, 1973;
Krombein, 1967
-
- Peckham & Peckham,
1898; Rau, 1928;
Krombein, 1967




================================================================================

Subfamily, tribe Species
Q attempts
Q associates to mate w/ Q deters Q assists wlindividual $ at or clepto- in nesting
nest near nest parasites activities Source Trypargilum texense
Trypargilum clavatum
Trypargilum politum
Trypargilum spinosum
Trypargilum orizabense
Trypargilum tridentatum
Trypargilum tenoctitlan
Crabroninae
Oxy belini Oxybelus subulatus
Oxybelus sericeus
Oxybelus emarginatus
Crabronini Lindenius panzeri
Lindenius columbianus
Lindenius armaticeps
Lindenius buccandentis
Nyssoninae
Stizini Stizus megastizus
-
Yes
Yes
-
-
-
yes?
no
no
no
no
no
no
no
texanus ves ves - no
Hartman, 1905
Rau, 1928; Krombein,
I967
Rau, 1928; Fattig, 1936
Lin, 1979
Coville, 1979
Krombein, 1967
Coville & Coville, 1980
Peckham et al., 1973;
Peckham, 1977
Bohart & Marsh, 1960;
Hook & Matthews, this
Paper
Krombein, 1964; Hook,
pers. obser.
Minkiewicz, 1934
Miller & Kurczewski,
1973
Ibid
I bid
Gillaspy, unpublished




================================================================================

34 Psyche [VOI. 87
would be further enhanced if males focused their territorial activity around active nests. If females exercise a preference for presence of a guarding male prior to initiating nesting (e.g. Trypargilum), then this behavior would spread in the population, since it would directly benefit the interests of both sexes. The possibility exists that males could ultimately be induced to guard nests without requiring repeated matings as is reported for Tachytes distinctus (Lin, 1963; Lin and Michener, 1972). However, such cases are in need of further study. In digger wasps, delays in provisioning and exposure to predators and cleptoparasites constitute important risks for females; but rejection of males may be costly in terms of time, energy and loss of resource (the nest). Such costs to the female must be important, otherwise females of 0. sericeus would not often attempt to sneak past guarding males when provisioning. Guarding males also incur real costs in addition to time and energy expenses. Gwynne and O'Neill(1980) recently showed that territoriality in Philanthus males resulted in increased mortality due to sex-biased predation. In Oxybelus sericeus the balance struck appears to effect a significant reduction in levels of cleptoparasitism, so male guarding directly benefits the interests of both sexes.
The multivoltine wasp Oxybelus sericeus nested continually from early May to October on St. Catherine's Island, Georgia. Nest sites were situated in sand just above a tidal salt marsh where the females hunted prey. Two otitid flies, Chaetopsis apicalis and C. aenea and one dolichopodid, Nanomyina litorea, comprised 96% of the prey. Up to three cells per day were stocked with an average of 7 (range 3 to 14) flies per cell. Prey were transported pedally from point of capture to the nest area whereupon females either continued pedal transport or impaled the fly on the sting before continuing to the nest. Number of cells per nest averaged 1.7 (range 1 to 6) with individual females varying the number of cells in successive nests. Cell depths averaged 7.9 cm (range 3.5 to 15). Males were active in the nest area and utilized five different mating strategies. Patrolling and nest guarding were the most common strategies. Certain individuals were found to dominate all other males in encounters in a small nesting area. These dominant males shifted their guarding activities to "track" actively nesting females for up to seven days. Miltogrammine fly parasitism ranged



================================================================================

19801 Hook & Matthews - Biology of Oxebelus 35 from 3.7% to 14.5%; Senotainia sp. was the predominant parasite, but Metopia sp. was also recorded. Ants (Solenopsispergandei Fore1 and Conomyrma sp.) were nest predators, with 13.5% cell mortality due to Solenopsis recorded at one site. Records of male association with nesting females are summarized from the literature. The idea is developed that the effect of a male's presence and activity in reducing mortality from cleptoparasitism supersedure has been an important factor in the evolution of male nest guarding and female's toleration of interference due to repeated copulation attempts. This work was supported by a grant awarded to R. W. Matthews by the Edward John Noble Foundation in conjunction with the American Museum of Natural History. Special thanks to J. T. Woods and staff for their support on the island: J. E. Gillaspy for the use of unpublished information; R. J. Gagne, L. Knutson, W. N. Mathis, G. C. Steyskal, F. C. Thompson, A. S. Menke and D. R. Smith of the I.I.I.P.I., USDA, for determination of prey specimens, cleptoparasitic flies, wasps and ants. R. M. Bohart of the University of California at Davis assisted in wasp determinations. J. W. Krispyn helped with the field work and preparation of the manuscript and D. J. Peckham and G. C. Eickwort critically reviewed the manuscript. ALCOCK, J.
1975. Territorial behaviour by males of Philanthus multimaculatus (Hymenop- tera: Specidae) with a review of territoriality in male sphecids. Anim. Behav. 23:889-895.
BOHART, R. M., AND P. M. MARSH
1960. Observations on the habits of Oxybelus sericeum Robertson (Hymenop- tera: Sphecidae). Pan-Pac. Ent. 36: 1 15-1 18. BOHART, R.M., AND A.S. Menke
1976.
Sphecid Wasps of the World: A generic revision. Berkeley, Calif.: University of California Press, 695 pp.
BOHART, R. M., AND E. I. SCHLINGER
1957. California wasps of the genus Oxybelus (Hymenoptera: Sphecidae, Crabroninae). Bull. Calif. Insect Surv. 4:103-143. BOORMAN, E., AND G. A. PARKER
1976. Sperm (ejaculate) competition in Drosophila melanogaster, and the reproductive value of females to males in relation to age and mating status. Ecol. Ent. 1: 145-155.




================================================================================

36 Psyche [vo~. 87
COVILLE, R. E.
1979.
Biological observations on Trypoxylon (Trypargilum) orizabense Richards in Arizona (Hymenoptera: Sphecidae). J. Kans. Ent. Soc. 52:613-620. COVILLE, R. E., AND P. L. COVILLE
1980.
Nesting biology and male behavior of Trypoxylon (Trypargilum) tenoctit- lan in Costa Rica (Hymenoptera: Sphecidae). Ann. Ent. Soc. Amer. 73:110-119.
EBERHABD, W. T.
1974.
The natural history and behavior of the wasp Trigonopsis cameronii Kohl (Sphfccidae). Trans. R. Ent. SOC. Lond. 125:295-328. EVANS, H. E.
1962.
The evolution of prey-carrying mechanisms in wasps. Evolution 26:468- 483.
FATTIG, P. W.
19.36.
Nesting building of Trypoxylon politforme Roh. Can. Ent. 68:44-45. GILLASPY, J. E.
1962.
Nesting behavior of @hex trepanecus Saussure (Hymenoptera: Sphecidae). Bull. Brooklyn Ent. Soc. 57: 15- 17.
GWYNNE, D. T., AND K. M. O'NEILL.
1980.
Territoriality in digger wasps results in sex-biased predation on males (Hymenoptera: Sphecidae, Philanthus). J. Kans. Ent. SOC. 53:220-224. HARTMAN, C.
1905.
Observations on the habits of some solitary wasps of Texas. Bull. Univ. Texas. 65: 1-73.
IWATA. K.
1942.
Comparative studies on the habits of solitary wasps. Tenthredo 4: 1- 142. KIMSEY, L. S.
1978.
Nesting and male behavior in Dynatus nigripes spinolae (Lepeletier) (Hymenoptera: Sphecidae). Pan-Pac. Ent. 54:65-68. KROMBEIN, K. V.
1958. Miscellanaeous prey records of solitary wasps. 111. (Hymenoptera, Aculeata). Proc. Biol. Soc. Wash. 71:21-26. 1964.
Results of the Archbold expeditions. No. 87. Biological notes on some Floridean wasps. (Hymenoptera, Aculeata). Amer. Mus. Novitates 2201:l-27.
1967.
Trap-nesting Wasps and Bees: Life Histories, Nests and Associates. Smithsoiiian Press, Washington, D. C. 570 pp. 1980.
Catalog of Hymenoptera in America North of Mexico. Vol. 2, 1645 pp. KURCZEWSKI, F. E.
1966.
Comparative behavior of male digger wasps of the genus Tachysphex (Hymenoptera: bphccidae, Larrinae). J. Kans. Ent. SOC. 39:436-453. LFFEVRE, G., AND U. B. JONSSON
1962.
Sperm transfer, storage, displacement, and utilization in Drosophila melanogasier. Genetics, Princeton 47: 17 19- 1736. LIN, c. s.
1979.
Biology of Trvpargilum spinosum, with notes on T. texense and T. politum at Lake Texoma (Hymenoptera: Sphecidae; Trypoxyloninae). Wasmann J. Biol. 27: 125- 133.




================================================================================

19801 Hook & Matthews - Biology of Oxebelus 37 LIN, N.
1963.
Territorial behavior of the cicada killer wasp, Sphecius speciosus (Dury) (Hymenoptera: Sphecidae). I. Behavior 20: 1 15- 133. LIN, N., AND C. D. MICHENER
1972.
Evolution of sociality in insects. Quart. Rev. Biol. 47: 13 1- 159. MASUDA, H.
1939.
Biological notes on Pison iwatai Yasumatsu. Mushi 12: 1 14- 146. MATTHEWS, R. W., A. HOOK, AND J. W. KRISPYN 1979.
Nesting Behavior of Crabro argusinus and C. hilaris (Hymenoptera: Specidae). Psyche 86: 149- 166.
MILLER, R. C., AND F. E. KURCZEWSKI
1973. Intraspecific interactions in aggregations of L,indenius (Hymenoptera: Specidae, Crabroninae). Insectes Sociaux 20:365-378. MINKIEWICZ, R.
1934.
Les types de comportement des males de Sphegiens. Polskie Pismo Ent. 13: 1-20.
PAETZEL, M. M.
1973. Behavior of the male Trypoxylon rubrocinctum. Pan-Pac, Entomol. 49:2&30.
PECKHAM, G. W., AND E. G. PECKHAM
1898.
On the instincts and habits of the solitary wasps. Wisconsin Geol. Nat. Hist. Survey, Sci. Ser., Bull. No. 2, 245 pp. PECKHAM, D. J., F. E. KURCZEWSKI, AND D. B. PECKHAM 1973.
Nesting behavior of Nearctic species of Oxybelus (Hymenoptera: Spheci- dae). Ann. Ent. Soc. Amer. 66:647-661.
PECKHAM, D. J.
1977.
Reduction of miltogrammine cleptoparasitism by male Oxybelus subula- tus (Hymenoptera: Sphecidae). Ann. Ent. Soc. Amer. 70:823-828. PECKHAM, D. J., AND A. W. HOOK
1980.
Behavioral observations on southeastern Oxybelus (Hymenoptera: Sphe- cidae). Ann. Ent. Soc. Amer. (In press)
RAU, P.
1928.
Field studies in the behavior of the non-social wasps. Trans. Acad. Sci. St. Louis 25325-489.
1933. The Jungle Bees and Wasps of Barro Colorado Island. Phil Rau, Kirkwood, Mo. 317 pp.
RIBI, W. A., AND L. RIBI
1979.
Natural history of the Australian digger wasp Sphex cognatus Smith (Hymenoptera: Sphecidae). J. Nat. Hist. 13:693-701. SMITH, R. L.
1979.
Repeated copulation and sperm precedence: paternity assurance for a male brooding water bug. Science 205: 1029- 103 1. STEINER, A. L.
1979.
Digger wasp predatory behavior (Hymenoptera: Sphecidae): fly hunting and capture by Oxybelus uniglumis (Crabroninae: Oxybelini); a case of extremely concentrated stinging pattern and prey nervous system. Can. J. Zool. 57:953-962.
TSUNEKI, K.
1970.
Gleanings on the bionomics of the East-Asiatic non-social wasps. VI. Some species of Trypoxyloninae. Etizenia 45: 1-20.



================================================================================




================================================================================