Mating Flight Research Articles

Mating flights of the queen honeybee ( Apis mellifera) in a subtropical climate

1. 1. Mating behaviour of queens and drones and mating success were studied throughout the year. 2. 2. Worker bees directed virgin queens to leave the hive and take mating flight. 3. 3. Cloudiness above 7 octavas and wind velocity above 3.9 m/sec. delayed queen and drone flights. 4. 4. Duration of queen flights was reduced at 15–20°C and wind velocity of 2.6–3.9 m/sec. 5. 5. The peak of flight activity hours of queens and drones overlapped throughout the year. 6. 6. CO 2 treatment of queens resulted in a delay of mating flight and in an enhancement of egg-laying. 7. 7. The queens successfully mated throughout one year. 8. 8. Colonies headed by 2–10-month old queens yielded similar honey crops.

Pheromonal activity and fine structure of the mandibular glands of honeybee drones ( Apis mellifera L.) (Insecta, Hymenoptera, Apidae)

Experiments were conducted to determine the role of drone mandibular gland secretions in attracting flying drones and the effect of age on the secretory activity. Extracts of mandibular glands and of cephalic tissues were applied to cotton lures which were attached below balloons tethered at 8–12 m above the ground. Most flying drones were attracted to extracts of mandibular glands but a few were drawn to other cephalic tissues or to solvent controls. Histological and electron microscope studies showed that the structure of the tiny (0.12 mm long) mandibular gland varied according to age. Its secretory activity in 0–3-day old drones was evident from the abundant rough endoplasmic reticulum. At 7-days the glands were fully developed. After 9 days the glands were no longer active and showed an autolytic process; the product was stored in the gland lumen for further emission during drone mating flights.

Aggression in wood ants (Formica polyctena Foerst., Hymenoptera, Formicidae)

The relationship between aggression and predation was surveyed in Red wood ants, in the field as well as under laboratory conditions. Aggression between wood ant nests is highest in early spring, and many wood ant wars break out then. The end of these wars coincides with a strong increase in prey density. Since the casualties are taken as food to the warring nests, a hypothesis is formulated that warfare between wood ant nests only occurs in periods when prey demand exceeds the supply. Protein-rich food in early spring is mainly for the benefit of the queens and the sexual larvae. Although the most obvious function of warfare is the defence of a foraging area, the main function may be the advancement of the mating flight dates of the queens in order to make the chance of propagating their genes greatest.

Polygyny and nuptial flight ofFormica (Formica) yessensis Forel at Ishikari Coast, Hokkaido, Japan

Polygyny and nuptial flight were observed in a supercolony of a Japanese red wood antFormica (Formica) yessensis Forel at Ishikari Coast, Hokkaido, Japan. The main results are: 1. The vertical distribution of queens in nests seasonally fluctuated, preferring deeper parts (mainly 40 to 60 cm below the ground surface) in hibernation season but shallower parts (10 to 40 cm) in summer. This fluctuation was significantly correlative with that of the vertical distribution of workers except mid July to prehibernation season. 2. In nests the queens tended to aggregate with each other at same chambers without hostility. They all had developed ovaries in egg laying season. 3. Abundant sexuals were produced in the average year, but occasional absence of such mass production was also possible. 4. The inseminated new queens tended to return to the mother colony, while most virgins tried to fly away.

Colony founding by pleometrosis in the fire ant, Solenopsis invicta

Newly mated queens of the fire ant, Solenopsis invicta, found colonies either alone (haplometrosis) or by joining with other newly mated queens (pleometrosis). Surveys after mating flights showed that nests and queens were usually aggregated in space, that queens were aggregated among occupied nest chambers, and that the occurrence and degree of pleometrosis was related to the mean queen density. Queens and nests were strongly associated with slightly higher ground, away from rainwash areas and puddles. The effects of queen density and microtopography (small hills) on pleometrosis were tested in a two-factor factorial experiment. A 64-fold increase in applied queen density resulted in a 2.19-fold increase in mean queens/nest (pleometrosis). Variation in queen density accounted for 70% of the variation in the mean queens per nest, as well as 78% of the aggregation of queens among the available nest chambers. Queen density also accounted for 86% of the aggregation of queens in area. Thus, at all densities, queens are moving into areas and nests of higher density, increasing both the local mean densities and the level of aggregation. Microtopography had no significant effect. Lab experiments suggest that the interactions leading to association take place on the surface. A mechanism is proposed in which the central causal factor regulating pleometrosis is local queen density, local being one to a few square meters, and a variety of factors affect pleometrosis by their action upon the local queen density. In the laboratory, groups of 5 foundresses produce more workers than do groups of 10 or 15, or single queens. Nests founded by groups begin the growth period with about 3 times as many workers as do those founded by single queens, and the former remain about three times as large for at least the first 100 days of growth and probably more. Higher worker production rate probably confers an advantage in survival and competition throughout colony growth. These differences between haplo- and pleometrotically founded nests may be among the factors favoring foundress associations.

Alate production and sex ratio in colonies of the Neotropical termite Nasutitermes corniger (Isoptera; Termitidae).

1. Dissections of 49 entire Nasutitermes corniger (Motschulsky) colonies collected in Panama immediately prior to the nuptial flights give data on numbers, biomass and sex ratio of alates produced by individual colonies. 2) Twenty-six other colonies were collected and dissected in the early period of alate nymph development. Alate nymphs proceed through five instars, spending 5-8 months within the parental colony. 3) Even when comparing colonies of similar size, variation in reproductive output among N. corniger colonies in a population is marked. Mature colonies (neuter population size 50,000-400,000) generally produce 5,000-25,000 alates, although some large colonies had no fertile brood, at least during the year they were censused. 4) On average, colonies which produce alates have 35% of the colony biomass invested in alates (or late instar nymphs) shortly before the nuptial flight. 5) Female N. corniger alates are 1.2-1.4 times heavier (dry weight) than male nestmates. Numerical sex ratio among colonies is skewed toward males, while biomass "investment" sex ratio is not significantly different from 1:1. These data conform to Fisher's amended theory of expected sex ratio.

The inhibitory pheromone of queen fire ants: effects of disinhibition on dealation and oviposition by virgin queens

1. Virgin queen fire ants,Solenopsis invicta Buren, that overwintered in parental nests participated in mating flights in early spring, and some were shown to have been laying eggs in queenright colonies before leaving. Virgin queens reared in spring had immature oocytes in their ovarioles when they left on mating flights. 2. When released from pheromonal queen influence by isolation, 98% of both overwintered and spring-reared virgin queens oviposited and exhibited colony founding behavior, but only 73% dealated. The alary muscles of all of them histolyzed, however, whether or not they dealated. The eggs laid by both the overwintered and springreared virgin queens were larger than those laid by physogastric mated queens, and less than 1% were viable. 3. When spring-reared virgin queens were disinhibited by dividing colonies into queenright and queenless halves, some virgin queens in the queenless halves dealated and oviposited. A frequency distribution of the sizes of eggs laid by these virgin replacement queens was bimodal. The larger eggs were similar in size to those laid by spring-reared virgin queens in isolation and less than 1% were embryonated. They served a trophic function. The smaller eggs were not as small as those laid by mated queens, but the majority were embryonated. The number of eggs laid by virgin replacement queens in 5 h was positively correlated with the maximum number of oocytes/ovariole. The size of eggs laid by virgin and mated queens was a function of the oviposition rate. 4. The results demonstrate that the inhibitory pheromone of queen fire ants acts directly on virgin queens and that it prevents muscle histolysis and rapid oogenesis. The former hypothesis that the pheromone acts mainly on workers and prevents them from causing virgin queens to dealate is, therefore, disproved. 5. A new working hypothesis consistent with the experimental results and with previously published information is that a single queen pheromone regulates the secretion, and titer, of juvenile hormone.

CITRONELLOL ATTRACTS MALE PRENOLEPIS IMPARIS (HYMENOPTERA: FORMICIDAE)

During studies of the attractiveness of essential oils to insects associated with Douglas-fir cones, traps baited with citronellol attracted male Prenolepis imparis (Say), the small honey ant. Citronellol was previously reported as present in the mandibular glands of worker and male ants (Law et al. 1965; Blum et al. 1968).The small honey ant is a ground nesting species frequently encountered in woodlands and noted for tending plant-sucking insects. Behavior of colonies has not been intensively studied, but it is known that alate ants leave the colony in March and April for a nuptial flight (Smith 1965).

An Altitudinal Comparison of Oxygen Consumption Rates in Three Species of Pogonomyrmex Harvester Ants (Hymenoptera: Formicidae)

The oxygen consumption rates at 30 C and the temperature sensitivity of the rates were compared for member groups (larvae, pupae, callows, workers, females, and males) of three species of harvester ants which occur at different altitudes in southern California. Developmental changes in both rates and temperature sensitivity were found. There is an abrupt doubling or tripling of the respiratory rates of males prior to the mating flights. No similar changes were found in the respiratory rates of the females. The males are dimorphic, with each size having different respiratory rates. In general, Pogonomyrmex montanus MacKay, the harvester ant from the highest altitude, had the highest respiratory rates and demonstrated the greatest temperature sensitivity. The mid-altitude species, P. subnitidus Emery, had intermediate respiratory rates. The lowest-altitude species, P. rugosus Emery, had the lowest respiratory rates and demonstrated the least temperature sensitivity. These differences are important as the ants are exposed to different temperature ranges; the higheraltitude species are exposed to lower temperatures. This physiological adaptation may be necessary to allow each of the species to be active at similar rates in the three different habitats. Although a physiological adaptation involving higher respiratory rates in ants from higher altitudes was determined in the three species investigated, it may not be a general phenomenon in ants. It is suggested that further investigation is needed to determine the parameters which have an effect on the important physiological process of respiration and to provide ecological interpretations for the differences observed.

Insect Swarming and Mating

The active aggregations of small animals are often called The term has been applied to the mass flight of workers and queen from a fissioning beehive, and to the dispersal flights of termite reproductives. Swarming in insects otherwise is generally a mating activity characterized by pair formation in flight. There is great variation among insect mating with regard to the degree of aggregation. Most fit into one of two classes, which are the extremes of a continuum. In one class, males fly throughout an area of female availability and are, more or less, evenly spaced. In the other, males are strongly clumped within a small portion of the volume where females are available and they tend to fly at a station for a prolonged period. I use the modifer to refer to swarming of the first class, while the unmodified is reserved for the second class. Gruhl (1955) proposed the terms synhesmia and synorchesia for the same purpose. The adoption of particular terms by other workers is not as desirable as is a general realization that there are important behavioral differences among various mating swarms, and that it is therefore often worthwhile to describe in considerable detail. Dispersed swarming describes situations in which males individually search for and pair with females while in flight and in sufficient density that someone has called the phenomenon a swarm. This activity occurs in areas where females are emerging, feeding, ovipositing, or dispersing when flight is integral to these pursuits. Males of some mayflies and caddisflies fly in great numbers over water and shoreline vegetation where females are emerging or resting, and intercept females as they fly (e.g. Needham et al. 1935, Solem 1978). Mass mating flights of ants may be synchronized over a large area (Sudd 1967). The swarms of lovebugs, Plecia nearetica (Bibionidae), seem to be dispersed (Thornhill 1980a) . Small dense of the second variety occupy a volume of a cubic meter or so and usually keep station with reference to some object. This object, the swarm (Downes 1969), generally has no value to the swarming species except its use in swarming, but flying males of some species may aggregate at resources where females may predictably occur, such as the hosts of blood feeding flies (e.g. Gubler and Bhattacharya 1972). Swarms may be closely spaced or separated by hundreds of meters, but in any case the greatest part of the volume within which females fly has a very low male density in comparison to the swarms. The process of assembly at a marker occurs in many insect species that do not mate in flight. Shields (1967) provides an extensive review of hilltopping behavior, which is the best known form of the phenomenon.

A study of multiple mating habit in Atta laevigata based on the DNA content

1. 1. Pure DNA was isolated from the genital organs of the Atta laevigata by the sodium dodecylsulfate method and chloroform-isoamyl alcohol treatment. 2. 2. The DNA content in sexual cells of winged mature subjects gives a new method in the analysis of multiple mating in such species of ants. 3. 3. From the data we concluded that each queen had at least three mates during the nuptial flight.

Weather conditions during nuptial flights of four European ant species.

In 1977, 1978, and 1979 nuptial flights of Lasius niger L., Lasius flavus F., Myrmica rubra L., and Myrmica scabrinodis Nyl. were observed on the island of Schiermonnikoog and in the area around Amsterdam. Weather conditions during these flights were determined using data from meteorological stations at Schiermonnikoog and Schiphol Airport. Significant differences were found concerning daytime, global radiation and relative humidity at the beginning of flights of Lasius niger, Lasius flavus, and Myrmica rubra; Myrmica scabrinodis had no defined preferences for these parameters. Wind velocity at 2 m of height was less than 1.7 m.s-1 during all flights before 20 August. After that date all species tended to fly at higher wind velocities as well.The calculated ranges for daytime, temperature, global radiation, relative humidity, and wind velocity appeared to be sufficient to characterize all nuptial flight occasions at Schiermonnikoog.Micrometeorological measurements in typical habitats of different ant species revealed that during flights the air temperature at 20 cm above ground and the soil temperature at 5 to 7 cm below ground were about equal in the habitat of the flying species, but unequal in the neighbouring habitats of coexisting ants.

Male induction and function of workers' excitability during swarming in leaf-cutting ants (AttaandAcromyrmex) (Hymenoptera, Formicidae)

Worker excitation in species of Atta and Acromyrmex prior to and during the swarming of reproductives is initiated by secretions from the male mandibular glands. During this phase, workers are highly aggressive, attacking all foreign objects. Field data suggest that this behavior is not only advantageous in protecting sexuals as they swarm, but also to prime workers to execute queens trying to initiate colonies near mature colonies following nuptial flights.

Life history and ecology ofStenonema modestum(Banks) (Ephemeroptera: Heptageniidae) in Virginia, USA

Abstract The life history and ecology of Stenonema modestum was investigated in the North Anna River, a 5th order stream in the Piedmont Physiographic Province of Virginia. S. modestum subimagines emerged in late‐afternoon to early‐evening from April to October. The duration of the subimago stage was ca. 24 hrs. There was seasonal size variation among adults with larger individuals emerging in the spring. There was also seasonal fluctuation in fecundity positively correlated with the seasonal variation in adult size. Nuptial flights occurred just before dusk with males forming swarms of 30–50 individuals above large riffles. Copulation occurred in the air. 5. modestum exhibited a multivoltine life cycle. Most of the overwintering brood emerged in April and deposited eggs; larvae from these eggs grew through the summer and emerged in mid‐August. Sporadic emergence of stragglers from the overwintering brood occurred throughout June and July; larvae from these eggs emerged in September and October. It appears that differential egg hatching was responsible for the continuous emergence pattern. There were at least 14 to 15 instars for the overwintering brood. Larvae were found most frequently under loose cobble and boulders. Larvae of S. modestum were opportunistic generalists in their feeding habits, primarily ingesting detritus and diatoms and occasionally early instars of Chironomidae.

The function of the post-pharyngeal glands of the red imported fire ant, Solenopsis invicta buren

Using radiolabelled triglycerides and fatty acids we have shown that these 2 lipids are absorbed into the haemolymph of the imported fire ant, Solenopsis invicta Buren from the post-pharyngeal gland. The post-pharyngeal glands attain their greatest weight and contain the highest hexane extractable lipid in establishing queens which have just reared the first minum brood. The lipid content of the digestive system is greatest in queens initiating a mating flight with the majority of the lipid contained in the crop. During colony establishment by the queen the lipid content of the crop moves forward, some is fed to the developing larvae and some moves into the post-pharyngeal gland. The hexane extractable lipid from the postpharyngeal gland of newly mated queens consists of hydrocarbons, sterols. tri-, di-, and monoglycerides and free fatty acids with a trace of wax esters. Excision of the post-pharyngeal glands from mated established queens causes no noticeable change in their behaviour or the behaviour they elicit from the remainder of the colony. However, post-pharyngeal glandectomized females lost weight and died in ca. 2 months although their crop and midgut contained food. The post-pharyngeal glands therefore appear to function in much the same way as a gastric caecum.

Mating flight ofPheidolesp. (Hymenoptera : Formicidae): note

Observations are presented on a mating flight of Pheidole sp. in Auckland.

Observations on the foraging activity of Hospitalitermes umbrinus (Haviland), (Isoptera: Termitidae) in the Gunong Mulu National Park, Sarawak

Abstract. 1. A single nest of the black surface‐foraging nasute termite Hospitalitermes umbrinus was studied for 5 days in July 1978. Foraging parties of workers and soldiers tend to leave the nest in a continuous stream in the evening and return carrying food balls during the following morning.2. An estimated maximum of 500000 individuals were involved in the foraging excursions. At a density of 3 nests ha‐1, the total foraging population is estimated as being at least 180 m‐2.3. The colony brought back an estimated 46.4 g (d.w.) of food in 4 days. The biomass of the colony was estimated at 349 g (d.w.) (c. 1396 g w.w.) excluding alates and the consumption at 8.3 mg (d.w.) g‐1 (w.w.) d‐1.4. The food balls were found to be of two types, light and dark coloured. The light balls contained wood constituents, bryophytes, blue‐green algae and fungal hyphae while the dark balls consisted mainly of lichens and their spores.5. Swarming began at 14.30 hours on 9 July and ended with the nuptial flight at 17.32 hours. About 3000 alates were released. They climbed to 9 m on a tree before taking off.

Factors Affecting the Distribution of Fire Ants in Texas (Myrmicinae: Formicidae)

County records for the fire ants, Solenopsis aurea, S. geminata, S. invicta, and S. xyloni, in Texas are reported. S. invicta was first reported in the state in 1953. Its spread in Texas is about 30 miles per year. This phenomenal spread is due to dispersal in nuptial flights and transport by water and man. Competitive displacement of native fire ants by S. invicta has been noted in Texas. The north- ward expansion of S. invicata will probably be limited by winter kill. It is speculated that S. invicta will eventually spread over the entire state and move southward into Mexico. The black imported fire ant, Solenopsis richteri Forel, was intro-

Distribution and post-settlement survival in the field by reproductive pairs ofHodotermes mossambicus Hagen (Isoptera, Hodotermitidae)

Debris-piles made byHodotermes mossambicus dealates digging-in after a nuptial flight were found in bushed grassland in central Kenya following unseasonal rain. Their density and survival were estimated, and their distribution examined. These are the first records of post-flight settlement density and survival in the field.

Mating behavior and sound production in harvester ants (Pogonomyrmex, Formicidae)

1. Stridulation sound production was investigated in sexuals of the harvester antsPogonomyrmex barbatus, P. rugosus andP. maricopa of the SW United States during preparation and take-off for nuptial flight, as well as during mate selection, copulation and postcopulatory behavior on the mating leks, and competition in the process of colony foundation. 2. The structures of the stridulatory organs and the characteristics of air-borne and of substrate-borne signals of the three species are described (Tables I and II). There are no prominent interspecies differences in the distress signals. 3. Stridulatory communication is not involved in the control of preflight warm-up and take-off for the nuptial flight. Further, it does not play a role in the selection of species and sex of the mates, or in the competition among males for females. 4. Females of all species stridulate regularly when prevented by males from leaving the lek after several copulations. It is assumed that this «female liberation signal» communicates the female's non-receptivity to approaching males and makes them let the female go. 5. Founding queens stridulate regularly when competing for founding burrows, especially if physical fights are involved. Nevertheless, our experimental results do not substantiate a communicatory function for this behavior.