Mating Flight Research Articles

Relation between the Level of Preimaginal Infestation by the Broodmite Varroa destructor and Adult Life Expectancy in Drone Honeybees (Hymenoptera: Apidae: Apis mellifera)

Varroa destructor Anderson & Trueman 2000 preferentially infests the drone brood of the European honeybee, Apis mellifera Linnaeus 1758. However, little is known about, how such infestations affect colony reproduction. The survival of drone honeybees was recorded as a function of different levels of Varroa infestation during their preimaginal development. In May and early June, drones emerging from uninfested brood cells lived a mean of 28 days. The life expectancy of parasitized drones was considerably shorter and depended on individual parasitic load. Since few infested drones lived till 12 days after emergence, when drones in Central Europe normally begin mating flights, varroatosis in Apis mellifera colonies significantly reduces the number of drones potentially participating in reproduction.

Biology and Laboratory Rearing of <I>Cricotopus lebetis</I> (Diptera: Chironomidae), a Natural Enemy of the Aquatic Weed Hydrilla (Hydrocharitaceae)

Field and laboratory studies were conducted on Cricotopus lebetis Sublette, a midge of unknown origin that causes widespread damage to the aquatic weed hydrilla, Hydrilla verticillata (L.f.) Royle, at Crystal River, FL, USA. The larvae of C. lebetis burrow into the submersed apical meristems of the hydrilla plant and destroy shoot tips during their development. Abscission of the hydrilla stem tip usually occurs when the last instar excavates a tunnel inside the stem for pupation. Mining damage caused by the feeding larvae induces stunting and basal branching that alters the normal growth pattern of hydrilla. Larval populations of C. lebetis and damaged hydrilla shoot tips were highest in the summer (May and June) and fall months (October and November) during 1997 and 1998. In June 1998, more than 70% of the hydrilla shoot tips were damaged by midge larvae. Adults lived <2 d in the laboratory, and nuptial flights were not a prerequisite for mating. Females deposited a single egg string containing an average of 154 eggs inside a gelatinous matrix. The eggs took ≈2 d to complete development and neonate eclosion was synchronized. The larval stage had four instars and required ≈14 d to develop to the pupal stage, which lasted an additional 2 d. Although most larval chironomids feed on algae or detritus, the larvae of C. lebetis fed and developed entirely on the living stem tissue of hydrilla.

Mechanism, induction factors, and adaptive significance of dealation in the subterranean termite Reticulitermes speratus (Isoptera, Rhinotermitidae)

We studied the dealation of a subterranean termite Reticulitermes speratus Kolbe from three different angles; mechanism, induction factors, and adaptive significance. During nuptial flight alates prevent the wings from breaking off by holding the wings in a 3-dimensional configuration. In the process of dealation, the alates hold the wings in a 2-dimensional configuration, half spread the wings in a lowered position, and bend the abdomen back toward the wings, thereby exerting high pressure at the basal sutures. This separates the wings from the body. The primary factor determining the timing of dealation appears to be isolation from other alates: It induces alates to shed their wings, whereas pairing has no effect on dealation in this species. Alates of termites are especially vulnerable to ant predation during the period between flight and colony foundation. An experiment designed to compare the risk of alates and dealates to predation by a termite-hunting ant, Brachyponera chinensis Emery, showed that dealation reduced the predation risk during the period spent running on the ground.

Occurrence of Winged Forms of Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae) in Laboratory Colonies

The production of hundreds of reproductive forms of Atta sexdens rubropilosa Forel in nests maintained in laboratory was observed for the first time in Brazil. Last instar male larvae were found on August 5, 2000 in a six-year-old colony with approximately 110 L of fungus garden distributed in 21 pots. Thirty to forty days later, queen larvae started to be seen. The adult sexual forms were comparable in size with those found in the field. Two apparent failed attempts of a nuptial flight were observed during the last week of October, followed by the appearance of dead males and females in the garbage piles of the colony.

Mate guarding and alternative reproductive tactics in the ant Hypoponera opacior

In many animals, males have evolved weapons, elaborate courtship displays, or costly ornaments to increase their reproductive success. Ants, in contrast, commonly mate during nuptial flights, in which males do not profit from fighting or attempting to monopolize females. However, where mating occurs in the nest, males can use other reproductive tactics. We found that wingless (apterous) males of Hypoponera opacior sat on top of queen cocoons, inserted their genitalia into the cocoons and remained in copula with cocooned queens for up to 40h. These males were tolerant of each other; fighting was never recorded. Our observations therefore suggest that wingless males of H.opacior ensure reproduction by copulatory mate guarding. This strategy, although time consuming, presumably reduces the likelihood of subsequent inseminations by other males. Apterous H.opacior males have only a limited amount of sperm available: histological preparations showed that, in contrast to Cardiocondyla fighter males, the testes degenerate in early adult life. Males ofH.opacior have relatively few mating opportunities. Although some wingless males were reproductively active for more than 3 weeks, we observed a maximum of only six matings per male, with a mean slightly above one. SomeH.opacior males used an alternative reproductive tactic of dispersal and outbreeding. We found colonies headed by single, dealate queens, which did not rear wingless sexuals but presumably reproduced through winged reproductives that mate in nuptial flights. The social structure of those colonies contrasted with nests containing wingless reproductives, which were highly polygynous and polydomous.

Identification and action of juvenile hormone III from sexually mature alate females of the red imported fire ant, Solenopsis invicta

Analysis of extracts of hemolymph obtained from sexually mature alate females of Solenopsis invicta from monogyne colonies resulted in identification of juvenile hormone III (JH III). The average amount of JH III was 0.32±0.04 pmol/μmolof hemolymph. Topical application of 0.038 pmol of JH III was sufficient to stimulate alates to shed their wings in the presence of the queen. The time in which alates were induced to dealate decreased linearly with increasing concentrations of JH III from 0.038 to 3.8 pmol. However, higher JH III concentrations deviated from linearity and did not reach dealation times comparable with those that occur after mating flights. Thus, it appears that the mechanism of dealation that occurs when female alates are out of the influence of their queen is different from the one associated with mating flights. Application of 0.42 μmol of precocene II inhibited dealation of alates in queenless colonies. However, this inhibition was reversed after applying 38 pmol JH III to precocene-treated alates. The sizes of corpora allata (CA) from sexuals treated with JH III did not differ from those of controls. However, the sizes of CA were reduced in alates treated with precocene II. The results indicated that JH was important to dealation.

Biased sperm use by polyandrous queens of the ant Proformica longiseta

The occurrence and genetic effects of polyandry were studied in the ant Proformica longiseta using three microsatellite markers. The average queen mating frequency (QMF) estimated from the sperm dissected from the spermathecae of 61 queens was 2.4 with 69% of the queens being multiply mated. QMF estimated from worker offspring in a subsample of eight monogynous colonies was 3.5, but the effective paternity (m e,p) was only 1.23. The difference between these values reflected unequal sperm use by the queens. Most colonies of P. longiseta were polygynous and the average relatedness among workers was 0.35. Polyandry thus added only marginally to the genetic diversity of colonies, and our results gave little support to the genetic-variability hypothesis for explaining polyandry. Diploid male load was low, as only 1% of males were diploid. A large majority (92%) of nests produced one sex only, with males produced in colonies that had higher than average worker relatedness. This contradicted the predictions derived from worker control of sex ratios. Males produced enough sperm to fill the spermathecae of several queens. Thus, the results indicated that diploid male load, sperm limitation and sex ratio conflict are also unlikely explanations of polyandry. Plausible hypotheses for polyandry include mating by convenience, as the sex ratio is male biased and the mating costs to a female can be low because the females are wingless and have no mating flight. The observed unequal sperm use furthermore points to sperm choice and sperm competition as important factors in the evolution of polyandry.

Reduction of Brain Volume Correlates with Behavioral Changes in Queen Ants

The behavior of reproductive female ants distinctly changes during the transition from virgin to mature, egg-laying queen. A winged female ant flies only once during her lifetime when she engages in the nuptial flight. Once she is mated she sheds her wings, excavates a nest and starts laying eggs, the basis for her future colony. We show for two species of harvester ants that this transition is accompanied by changes in the performance of behavioral tests: flying virgins are positively phototactic and prefer open areas, whereas young queens prefer the dark, avoid open areas and, given the opportunity, dig into the soil. These behavioral changes coincide with morphological changes in the brain. The brains of mature queens are significantly smaller than those of virgin females at the time of their mating flight. A disproportionately large shrinkage occurs in the medulla and other parts of the visual system during the early adult life of the queen. The brain reduction appears to be adaptive as mature queens show reduced behavioral repertoires and live in the dark. In contrast to virgin females, they do not rely on vision and might increase their fitness by reducing metabolically costly neural tissue.

Copulation and male calling in the swift moth, Endoclita excrescens(Butler)(Lepidoptera: Hepialidae).

Actual copulations of the swift moth, Endoclita excrescens (Butler), were recorded both in field observations at Takasaki in Kukizaki Town, Ibaraki Prefecture, Japan and in a large cage at the Forestry and Forest Products Research Institute during a research period from 1 September to 7 October 1999. Copulations took place during the dusk flight and the complete process of successful mating behavior in E. excrescens was observed. This demonstrates that the dusk flight of E. excrescens is the mating flight. In the beginning of the mating behavior, the female(s) flew straight toward the male(s) showing a swinglike pendulum flight around a branch of a particular tree in a particular spot. This result shows female attraction by the males (male “calling”). Preliminary experiments suggest that females are attracted to the flying males by visual cues from a long distance and the male scent from a short distance in the final encounter. The male flight pattern including the swinglike pendulum flight may have a “calling” function in long-range female attraction.

Queen primer pheromone affects conspecific fire ant ( Solenopsis invicta ) aggression

Monogyne fire ant, Solenopsis invicta, colony workers are territorial and are aggressive toward members of other fire ant colonies. In contrast, polygyne colony workers are not aggressive toward non-nestmates, presumably due to broader exposure to heritable and environmentally derived nestmate recognition cues (broad template). Workers from both monogyne and polygyne fire ant colonies execute newly mated queens after mating flights. We discovered that monogyne and polygyne queens have a remarkable effect on conspecific recognition. After removal of their colony queen, monogyne worker aggression toward non-nestmate conspecifics quickly drops to merely investigative levels; however, heterospecific recognition/aggression remains high. Queenless monogyne or polygyne worker groups were also not aggressive toward newly mated queens. Queenless worker groups of both forms that adopted a monogyne-derived newly mated queen became aggressive toward non-nestmate workers and newly mated queens. We propose that the powerful effect of fire ant queens on conspecific nestmate recognition is caused by a queen-produced recognition primer pheromone that increases the sensitivity of workers to subtle quantitative differences in nestmate recognition cues. This primer pheromone prevents the adoption of newly mated queens (regulation of reproductive competition) in S. invicta and when absent allows queenless workers to adopt a new queen readily. This extraordinary discovery has broad implications regarding monogyne and polygyne colony and population dynamics.

Dusk mating flight in the swift moth, Endoclita excrescens(Butler)(Lepidoptera: Hepialidae).

Laboratory-reared and wild adults of Endoclita excrescens (Butler) showed a mating flight at dusk. They began to fly soon after sunset and stopped flying at the beginning of darkness both in the cage and in the field (a forest in Chiyoda Town, Ibaraki Prefecture, Japan) during the period from 1 June to 20 October 1998. It is suggested that their flight activity is closely related to light intensity. Usually, the males began their flying about 4 min prior to the female flight. Mean flight period of the males per night was about 15 min in the cage and about 7 min in the field. For the females, it was about 10 min in the cage and 2 min in the field. The flight behavior of males was strikingly different from that of the females. The males flew swiftly and often showed a swinglike pendulum flight but the females did not. The males flew around a branch of a particular tree in a particular spot and sometimes formed a small group consisting of 2 to 4 individuals. Although no actual copulation was recorded, all other phases in the mating behavior were observed.

Comparison of reproductive strategies and raiding behaviour in facultative and obligatory slave-making ants: the case of Formica sanguinea and Polyergus rufescens

A review of field and laboratory research concerning raiding behaviour, mating strategies and colony founding in Formica sanguinea and Polyergus rufescens (respectively facultative and obligatory parasites of the Serviformica species) is presented. The analysis and comparison of these crucial and peculiar moments in the life cycle of dulotic colonies may be a valid tool to clarify the evolutionary origins of slavery in ants.¶Concerning the reproductive behaviour, F. sanguinea females mate only in nuptial flights. P. rufescens females mate on the ground around their natal nest, or return to a dulotic colony after mating flights and wait for a raid, or mate directly during a raid. Moreover, field observations suggest that F. sanguinea adopts a strategy similar to the "male aggregation syndrome", whereas P. rufescens mating strategy can be considered similar to the "female calling syndrome". In the field, newly-mated queens of both slave-makers participate in raiding swarms: following a slave raid is an advantageous strategy to locate and invade host nests and to establish a new dulotic colony.¶For colony formation, F. sanguinea presents a great variety of possible strategies (independent foundation and dependent foundation including alliance, adoption, usurpation, and brood sack). This provides evidence of a behavioural plasticity that confirms its nature as a facultative parasite. On the contrary, P. rufescens depends only on usurpation, during which the Dufour's gland contents seem to play a crucial role in the appeasement of the residents of the target colony.¶Also the raiding behaviour of F. sanguinea is less specialized than that shown by P. rufescens. In fact, in the obligatory slave-maker the important role of scouts in the organization of slave-raids is confirmed, which are rapid and effective. By contrast, raids of F. sanguinea may be regarded as a continuation and expansion of common foraging and predatory activity, as predicted by Darwin's hypothesis for the origin and evolution of slavery in ants. Nevertheless, the intraspecific raids conducted by P. rufescens emphasize also the important role of territorial competition as evolutive cause of dulosis.

Continuous transfer of subterranean mealybugs (Hemiptera, Pseudococcidae) by Pseudolasius spp. (Hymenoptera, Formicidae) during colony fission?

In West- and East-Malaysian lowland rainforests, three Pseudolasius spp. are found in trophobiotic relationship with a total of eight scale insect species in six genera feeding at the roots of plants. Intimate associations going beyond pure trophobiosis could be discovered with five species of root mealybugs: Planococcoides sp., Maconellicoccus multipori (Takahashi) and three species of Rhizoecus. All three Pseudolasius species carry their pseudococcids 1. when disturbed, 2. during nest movements, and 3. to feeding sites. Moreover, the Pseudolasius species under discussion permanently keep adults and immature instars of their mealybug partners within their nests.¶Pseudolasius spp. are highly polydomous, which results in an extremely decentralized colony structure. Numerous small nest chambers were either widely distributed in the top soil (Pseudolasius sp. 2 and sp. 3) or predominantly in small decaying twigs (Pseudolasius sp.1). Pseudolasius sp.1 and Pseudolasius sp. 2 are polygynous. Of Pseudolasius sp. 3 we found only one queen, but polygyny is highly probable as well. Mealybug-carrying or phoresis during mating flights could not be observed. Nevertheless, Pseudolasius sp.1 was found associated with Rhizoecus sp. #21, being widely distributed in the humus layer from 600 m a.s.l. up to 1140 m a.s.l. (at Mt. Kinabalu, Sabah, East-Malaysia). In 81.7% of the nests, Rhizoecus sp. #21 was present. Preferences for certain mealybug species were detected for Pseudolasius sp. 1, P. sp. 2 and P. sp. 3 in West-Malaysia as well. Consequently the question arises how the simultaneous distribution of both partners is achieved.¶For the co-dispersal of Pseudolasius spp. and their pseudococcids we suppose queen adoption and permanent colony fission take place, possibly combined with claustral colony foundation and the help of independently gained root trophobionts.

Genetic variability and social structure of Colonies in Acromyrmex heyeri and A. striatus (Hymenoptera: Formicidae).

The breeding structure of both colony and population of social insects can be examined by genetic analysis. Colonies of the leaf-cutting ants Acromyrmex heyeri and A. striatus (Myrmicinae, Attini) were thus analyzed for isoenzyme systems MDH, a-GPDH, and AMY to describe genotype variability and social structure. A total of five loci were investigated (three for amylase and one for each other system). Ninety-seven colonies of A. heyeri and 103 of A. striatus were sampled in different localities in Southern Brazil (State of Rio Grande do Sul). The genotypes found show the occurrence of monogyny and polygyny associated or not with polyandry, which indicates that the social organization is colony-specific. The polygyny and polyandry observed are likely to be responsible for the great genotypic diversity of the colonies. The average inbreeding coefficient per colony was higher in A. striatus than in A. heyeri, which may reflect the different patterns of production of sexual individuals and nuptial flight of those two species.

Microgeographic genetic structure and intraspecific parasitism in the antLeptothorax nylanderi

Summary1. Genetic colony structure of the small central European antLeptothorax nylanderiis affected strongly by ecological constraints such as nest site availability and intraspecific social parasitism.2. AlthoughL. nylanderiis generally monogynous and monandrous, more than a quarter of all nests collected in a dense population near Würzburg, Germany, contained several matrilines. As shown by microsatellite analysis, the average nest‐mate relatedness in these nests was 0.20. Genetically heterogeneous nests arise from nest take‐over by alien colonies or founding queens, a result of severe competition for nest sites.3. In summer, more than one‐third of all colonies inhabited several nest sites at a time. Polydomy appears to be rather limited, with two or three nests belonging to a single polydomous colony.4. Queens appear to dominate male production; only a small fraction (8%) of males was definitively not progeny of the queen present but might have been worker progeny or offspring of another queen.5. Strong evidence for heterozygote deficiency was found and a total of nine diploid males was discovered in two colonies. These findings suggest deviation from random mating through small, localised nuptial flights.

Biological constraints and colony founding in the polygynous invasive ant Lasius neglectus (Hymenoptera, Formicidae)

The polygynous invasive ant Lasius neglectus was described from Budapest, Hungary, as an unicolonial species, with no apparent colony barriers, and inferred intra-nidal mating without a nuptial flight. Here we analyze additional morphological characteristics of gynes, their physiological condition at emergence and at the time of mating and we describe the productivity of different types of colony founding in the laboratory. A low increase in dry weight and in fat content from emergence to mating indicates that gynes can only succeed in dependent colony founding. However, the queen-worker thorax volume ratio is typical of a species with independent colony founding and we were able to demonstrate independent colony founding in the laboratory (both haplo- and pleometrotic). Brood development in independent founding is rapid and the number of nanitics higher than in other Lasius species. Both colony budding and dependent colony founding could also be demonstrated in the laboratory. Worker oviposition was absent. The carbohydrate content of newly mated queens is consistent with the observed loss of mating flight of this species. However the relative wing area clearly indicates that L. neglectus queens should be able to fly. Therefore, both queen morphology and physiological state at maturity show that L. neglectus is intermediate between a monogynous, free-living, non pest ant and a multiqueened (polygynic) invasive tramp ant. This neglected ant thus offers interesting opportunities to study the origin of unicoloniality and the spread of this species in northeast Spain.

Ant and human farmers face similar problems.

Ants of the tribe Attini discovered agriculture 50 million years before humans (Mueller et al 1998). Today, nearly 200 species in 12 genera of these ants cultivate fungus gardens in the Nearctic and Neotropical regions; in the Palaeotropics, this niche is occupied by fungus-growing termites. It is believed that the act of fungus cultivation evolved just once in the attines (Wilson 1971). The primitive attines cultivate fungus on insect frass and decaying vegetation while the advanced attines are the eponymous leaf-cutting ants. These ants carefully select leaves from species that are low in fungistatic compounds, such as phenolics, carry them to underground nests where they are masticated, and plant them in soil along with fungal mycelia and glandular secretions containing proteolytic enzymes. Obligate fungal symbionts break down structural carbohydrates in the leaves and produce nutritive protruberances called gongylidia from their hyphae. The ants consume these gongylidia and also feed them to their larvae. They also prevent the fungi from forming fruiting bodies or sporophores; consequently, the fungus is clonally propagated. In the advanced attines, the queen tucks a pellet of the mutualistic fungal mycelia into her infrabuccal pouch before her nuptial flight, and then uses this fungal innoculum to seed a new fungus garden in the new colony.

Mating behavior of dimorphic reproductives of the ponerine ant, Hypoponera nubatama

Both wingless worker-like queens, and dealated queens of the ponerine ant, Hypoponera nubatama, engage in egg-laying activities. Corresponding to the differentiation in female reproductives, males are also dimorphic, winged and ergatoid. In Japan, wingless reproductives appear mainly from late July to mid-August, while winged ones appear mainly from late August to mid-October. Winged reproductives make nuptial flights, while wingless ones mate inside the nests. Cross-mating is, however, possible in the laboratory. The mating of ergatoid males is characterized by very long precopulation and copulation times, frequently more than 2 hours, suggesting that ergatoid males themselves play the role of mating plug. We observed no fighting among ergatoid males. However, they did seem to cause a relatively higher mortality rate in rival ergatoid males by embracing them while still in the cocoon.

Structural differences in the drone olfactory system of two phylogenetically distant Apis species, A. florea and A. mellifera.

Male insects that are attracted by sex pheromones to find their female mates over long distances have specialized olfactory subsystems. Morphologically, these subsystems are characterized by a large number of receptor neurons sensitive to components of the female's pheromones and hypertrophied glomerular subunits ('macroglomeruli' or 'macroglomerular complexes') in the antennal lobes, in which the axons of the receptor neurons converge. The olfactory subsystems are adapted for an increased sensitivity to perceive minute amounts of pheromones. In Apis mellifera, drones have 18,600 olfactory poreplate sensilla per antenna, each equipped with receptor neurons sensitive to the queen's sex pheromone, and four voluminous macroglomeruli (MG1-MG4) in the antennal lobes. In contrast, we show that drones of the phylogenetically distant species, Apis florea, have only 1,200 poreplate sensilla per antenna and only two macroglomeruli in their antennal lobes. These macroglomeruli are homologous in anatomical position to the two most prominent macroglomeruli in A. mellifera, the MG1 and MG2, but they are much smaller in size. The morphological and anatomical differences described here suggest major modifications in the sex-pheromone processing subsystem of both species: (1) less pheromone sensitivity in A. florea and (2) a more complex sex-pheromone processing and thus a more complex sex-pheromone communication in A. mellifera. Research in honey bee sex-pheromone communication dates back to the 1960s, when Gary (1962) demonstrated that in Apis mellifera the queen's mandibular gland secretion and especially its main component, 9-ODA (9-keto-2(E)-decenoic acid), is highly attractive to drones on their nuptial flight. Later, cross-species attraction experiments showed that other honey bee species, Apis florea, A. cerana, and A. dorsata probably also use the queen's mandibular gland secretion as a mating attractant (Butler et al. 1967; Sanasi et al. 1971). Besides its function in mating behavior, the queen's mandibular gland secretion is the main pheromone regulating queen-worker interactions (Free 1987). In this context, several studies have demonstrated the behavioral significance of single components (Slessor et al. 1988) and differences in the composition of the secretion between Apis species (Plettner et al. 1996, 1997; Keeling et al. 2000). Regarding the interspecific differences in the queen's signal, the question arises whether this variation is reflected in the olfactory system of drones and workers of the various species.

The role of pheromones and biostimulation in animal reproduction

It is now known that pheromonal communication plays an important role in mammalian behaviour and reproductive processes. Chemical communication with pheromones is one means of transmitting such information. In mammals, signalling and priming pheromones are thought to act either singly or in combination through olfaction, auditory, visual (sight) or tactile stimuli. Pheromones are air-borne chemical substances (“signals”) released in the urine or feces of animals or secreted from cutaneous glands that are perceived by the olfactory system and that elicit both behavioural and endocrine responses in conspecifics. Extensive studies in insects, rodents, swine, sheep, goats and cattle have established the importance of pheromones in the strong influence exerted by the male on reproductive activity in the female. There is a pheromone produced by the queen honey bee, which has two functions: inhibition of queen rearing and suppression of oogenesis in workers and in addition attracts drones during nuptial flight. It has also been demonstrated that the urine of male mice, rats, feral species and other wild rodents contains a priming pheromone that is responsible for hastening puberty in the females. Pheromones in the wool, wax and urine of a ram are sufficient to stimulate ewes to ovulate, while the buck has a strong characteristic seasonal odor and a buck jar containing the odor of the buck can be used as an aid in the detection of oestrus in does. The mere presence of the boar at the time of insemination of the sow improves sperm transport and ovulation, while the presence of the vasectomised bull has been reported to hasten the onset of puberty in heifers and also early resumption of ovarian activity in cattle following parturition. The role of pheromones in bovine reproduction is not as clearly defined as in sheep, goats and swine. Pheromones and other allelomimetic cues can exert profound effects on reproductive activity via the hypothalamic system that generates pulses of gonadotropin-releasing hormone. Manipulations of these factors and other pathways linking environmental inputs to reproductive output can lead to developing the concept of “control systems technologies”, aimed at controlling reproductive performance. The knowledge acquired on the effectiveness of biostimulation; the factor which conditions it and the biological mechanism which produces it in livestock species, allows its use as a breeding management tool. The understanding of the role of pheromones could be of potential economic importance in addressing some of the problems associated with livestock production in the tropics. The biostimulation technique offers a potentially useful and practical way to improve reproductive efficiency in livestock species in the tropics. The exact nature of the cues and the role of biostimulation in livestock species especially swine, sheep, goats and cattle in developing countries require more attention.