Sphecius Research Articles

Control of Cicada Killer with Individual Burrow Sprays, 1990

Abstract Five insecticides were evaluated as water based sprays applied directly into and at the burrow entrance only for control of cicada killer wasps on a golf course fairway. Ten active burrows were selected for treatment with each insecticide and marked with stake wire flags. Sprays were applied with a 1.5 gal compression sprayer. Five burrows were treated by inserting the spray nozzle about 1 inch into the burrow, releasing the spray solution and then applying a small amount of spray to excavated soil just outside the entrance as the nozzle was removed from the burrow. The second set of 5 burrows was treated by applying the spray only to the small area of excavated soil at the burrow entrance. The avg amt of spray used for treating all burrows ranged from 25 to 35 ml/burrow. Control evaluation was based on the absence of digging activity by wasps at treated burrows 3 DAT; untreated nearby burrows were checked for digging activity at the same time.

Control of Cicada Killer with Area Sprays on a Golf Course, 1990

Abstract Four insecticides were evaluated as spray treatments over areas ranging in size from 46 to 130 m2. Treatments were not replicated. Sampling consisted of counting active burrows within the confines of a 1/3 m2 wire hoop randomly tossed into the treated area; counts were made in 3 areas/treatment each date. Sprays were applied 26 Jul with a 1.5 gal compressor sprayer at the rate of 2 liters/9.3 m2. Treated areas were not irrigated but about 0.4 inches of rain fell on the plot site about 1/2 h after treatment. Treated areas were only sparcely covered with grass and there was no thatch layer. Soil type is sand consisting of 90.0% sand, 6.4% silt, and 3.6% clay. Cumulative precipitation during the trial at 6, 8, 13, and 20 DAT was 0.40, 0.40, 0.65, and 0.75 inches, respectively.

Protandry in western cicada killer wasps, (Sphecius grandis, Hymenoptera: Sphecidae): an empirical study of emergence time and mating opportunity

Sphecius grandis is a univoltine, colonial wasp. Females mate once and are sexually receptive when they emerge in July and early August. Males generally emerge earlier in the summer than females. The opportunity for each male to acquire mates is a function of the number of females emerging during his lifetime and the number of competitiors that are active when the females emerge. I determined a mating opportunity index (MOI) for each male in an aggregation of wasps for three separate summers, and correlated the MOI of individual males with their emergence date. The MOI of a male estimates the potential contribution that timing of emergence makes to his reproductive success. In 1984 males emerging near the mean of the male emergence distribution had the highest MOI. These males emerged between one and two weeks prior to the mean female emergence date. However, in 1981 late emerging males had the highest MOI. In 1983 there was no significant difference in MOI among males. As a result of between-year variation in female emergence schedules and in the duration of male lifetime, the selection pressures influencing male emergence time vary between years.

Cicada Killer, Giant Ground Hornet, Sphecius hogardii (Latreille) and Sphecius speciosus (Drury) (Insecta: Hymenoptera: Sphecidae)

Cicada killers, or giant ground hornets, are among the largest wasps in Florida (up to 40 mm in length). They are conspicuous insects, since the males are territorial and will butt or grapple with intruders including other males. There are 22 species of Sphecius Dahlbom in the world and all hunt cicadas as far as is known. Two of four Nearctic species of Sphecius occur in Florida. The females of the common Florida species, Sphecius speciosus (Drury), hunt Tibicen spp. cicadas and can dig 4-foot burrows in the ground with several branches and cells. The provisioning with cicadas is nearly specific to Sphecius in the family Sphecidae, but is known in a few other sphecids such as Liogorytes joergenseni (Brethes) from Argentina (Bohart and Stange 1976). This document is EENY295, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date June 2003. Revised January 10, 2005. 
 EENY295/IN573: Cicada Killer, Giant Ground Hornet, Sphecius hogardii (Latreille) and Sphecius speciosus (Drury) (Insecta: Hymenoptera: Sphecidae) (ufl.edu)

Role differentiation in copulating cicada killer wasps.

Copulating male and female cicada killer wasps have distinct behavioral roles independent of reproduction. Males terminate copulation, and females initiate the copulatory flight in which the pair in copulation escape potential danger. Separation and escape behavior are mutually exclusive. Separation occurs because the female clings to the substrate and fails to join the male in his frequent attempts at flight; thus he eventually pulls free. Escape occurs when the female begins flight, which the male readily joins. Differences in thresholds for flight probably largely determine both roles. There appears to be an evolutionary balance in escape and separation behavior determined by the behavior of the female, and illustrative of behavioral homeostasis. The female remains still in the presence of mild stimuli, such as attempted male flights, and thereby aids in separation; she initiates escape in the presence of strong stimuli such as potential enemies.

Territorial Behavior in the Cicada Killer Wasp Sphecius Speciosus (Drury) (Hymenoptera: Sphecidae). I

Male cicada killers (Sphecius speciosus) set up territories which are defended against intrusion by other males, other insects, and even thrown pebbles. Territory owners continually return to territorial perches, usually emergence holes. There is no apparent tendency for wasps to utilize their own holes of emergence as territorial perches. Aggressive flights by the owner terminate in one of four fashions, depending on the type of intruder and its behavior. Non-aggressive males and non-aggressive insects of other species are pursued without the owner getting within striking distance. Nonaggresive, slow-flying forms of other insect species are overtaken, and after an aggressive approach (here termed threat) the owner abruptly ends the chase. Non-aggressive male wasps or slow-flying insects of other species are butted by the owner. Grappling occurs with aggressive conspecific males and occasionally with non-aggressive conspecific males. Aggressive intrusion occurs when the intruder possesses an adjacent territory and first reacts to his neighbor while over his own territory. Most territories are set up in areas of high emergence hole density. Territorial behavior enhances mating efficiency by spacing the males and thereby increasing the frequency of male-female interaction. Localizing of territories in places of high emergence hole density fosters male-female interaction because the owners are more likely to contact emerging females. Mating efficiency is also probably enhanced by a reduction in the frequency of male-male interactions, thereby reducing the interference of superfluous males during precopulatory behavior.

The Relation of the Prey of Sphecius Speciosus to the Size and Sex of the Adult Wasp (Hym.: Sphecidae)

It has frequently been observed that the female cicada killer, Sphecius speciosus (Drury), provisions each cell of her nest with one or two cicadas. As the sexes of the adult wasp show a considerable difference in average size, the male being much smaller, it is natural to ask: does the sex of an adult bear any relation to the amount of prey with which its cell was provided? In other words, are the sex and size of the adult wasp directly correlated with the number and weight of the stored cicadas? Though I am far from reaching any final answers, it seemed worth while to put my present results on record, especially as they suggest one or more promising lines of investigation which I have no immediate prospect of being able to follow.