Oecophylla Longinoda Latreille Research Articles

Overview and future research needs for development of effective biocontrol strategies for management of Bactrocera dorsalis Hendel (Diptera: Tephritidae) in sub-Saharan Africa.

Infestation of fruits by native and invasive fruit flies causes significant economic losses. In most cases, incidence of 'regulated' dangerous fruit flies in orchards results in restrictions on export of fruits from such places to international markets. Unfortunately, use of insecticides applied on foliage and fruits does not kill the fruit-to-soil stages of fruit flies. However, diverse biological control agents (BCAs) do so. Thus, prevalence of native and invasive fruit flies in orchards will require that a combination of BCAs is included in integrated pest management (IPM) programmes. In the case of Bactrocera dorsalis Hendel and other economically important fruit flies found in sub-Saharan Africa (SSA), use of classical biocontrol approach involves concomitant releases of two exotic parasitoids (Fopius arisanus Sonan and Diachasmimorpha longicaudata Ashmead). These non-native wasps may have complemented the indigenous parasitoids in combination with application of entomopathogenic fungi (EPFs) and conservation of predatory ants (Oecophylla longinoda Latreille, with O. smaragdina) in fruit fly IPM plans. Consequently, some levels of decline in fruit infestation have been observed. Although interspecific interactions between BCAs against several insect pests have produced varying results, including threatening the survival of other BCAs, the prevalence of B. dorsalis in orchards across SSA requires further research to investigate effects of coalescing biocontrol approaches in IPM strategies. Therefore, future research into combining parasitoids, EPFs and entomopathogenic nematodes, in addition to conservation of predatory ants (O. longinoda, O. smaragdina and others) in IPM plans may improve the effectiveness of currently used strategies for the management of fruit-infesting tephritids. © 2021 Society of Chemical Industry.

Notaferrum n. gen. (Coleoptera: Ptinidae): the first known spider beetle associated with weaver ants

A new genus name Notaferrum n. gen. is proposed for Ptinus natalensisPic, 1906. The taxon is diagnosed and described and the only known species redescribed. This taxon, well outside the concept of the genus Ptinus Linnaeus, 1766, is most distinctly characterized by a pair of longitudinal and vertically oriented blade-like ridges located medially on the pronotum, a previously unknown feature in the spider beetles and the more inclusive Bostrichoidea Latreille, 1802. This species is a probable symphile of the African species of weaver ant (Oecophylla longinoda Latreille, 1802), based on both a collection record from inside an ant nest as well as the presence of distinct trichomes on the pronotum. This taxon represents the first record of a spider beetle associated with weaver ants.

Identifying Ant-Mirid Spatial Interactions to Improve Biological Control in Cacao-Based Agroforestry System.

The use of ants for biological control of insect pests was the first reported case of conservation biological control. Direct and indirect community interactions between ants and pests lead to differential spatial pattern. We investigated spatial interactions between mirids, the major cocoa pest in West Africa and numerically dominant ant species, using bivariate point pattern analysis to identify potential biological control agents. We assume that potential biological control agents should display negative spatial interactions with mirids considering their niche overlap. The mirid/ant data were collected in complex cacao-based agroforestry systems sampled in three agroecological areas over a forest-savannah gradient in Cameroon. Three species, Crematogaster striatula Emery (Hymenoptera: Formicidae), Crematogaster clariventris Mayr (Hymenoptera: Formicidae), and Oecophylla longinoda Latreille (Hymenoptera: Formicidae) with high predator and aggressive behaviors were identified as dominant and showed negative spatial relationships with mirids. The weaver ant, O. longinoda was identified as the only potential biological control agent, considering its ubiquity in the plots, the similarity in niche requirements, and the spatial segregation with mirids resulting probably from exclusion mechanisms. Combining bivariate point pattern analysis to good knowledge of insect ecology was an effective method to identify a potentially good biological control agent.

Ant-mediated ecosystem services and disservices on marketable yield in cocoa agroforestry systems

Abstract The impact of complex direct and indirect interactions between multiple functional groups on plants is poorly documented. In tropical agroecosystems, ants interact with crop mutualists and antagonists, however, little is known about effects of dominants ant community properties on the consequence of such cascading interactions which can be measured through final ecosystem service, crop yield. Here, we present a replicated ant fauna manipulation experiment in cocoa agroecosystems, where we used ant exclusion treatments to test the economic importance of the presence of ants, and two additional treatments where we experimentally introduced one of two common dominant ant species which allowed comparing their effects with those of the naturally occurring ant fauna. The proximate aim was to assess the impact of ants Crematogaster sp., Camponotus brutus Auguste-Henri Forel and Oecophylla longinoda Latreille on cacao yield, which is known to depend on several, cascading intermediate ecosystem services (e.g. control of specific pests). Ants provided ecosystem services in term of reduced pest damage caused by Salhbergella singularis Hagh (Hemiptera: Miridae) and Characoma stictigrapta Hmps (Lepidoptera: Noctuidae) but also disservices such as increased pathogen disease caused by Phyphthora megakarya Brasier and Griffin dissemination and indirectly enhanced damage of other pest species. Yields were highest in non-manipulated and species-rich ant communities, whereas ant exclusion and communities dominated by a single species decreased yield by more than 30%. Associated ant communities between dominant and non-dominant species resulted in the same yields as in non-manipulated controls. Dominant ant communities maximized the control of a particular pest species, but not cacao yield. We show a positive relationship between ant species rich communities and financial performance and we postulate that complex agroecosystems can offer competitive business opportunities for small-scale farmers, while contributing to biodiversity conservation. However, more interdisciplinary studies are needed to quantify financial and biodiversity performance opportunities to allow up-scaling of these findings.

Interaction Between African Weaver Ant Oecophylla longinoda and Dominant Ant Species Pheidole megacephala and Anoplolepis custodiens in Cashew Fields in Tanzania

The interaction between the African weaver ant (AWA), Oecophylla longinoda Latreille, and dominant ant species, the big-headed ant (BHA), Pheidole megacephala Fabricius, and the common pugnacious ant (CPA), Anoplolepis custodiens Smith, was examined in the cashew fields at Bagamoyo and Mkuranga districts, Coast region of Tanzania. Sugar-based bait was used monthly to examine the interaction between AWA, BHA, and CPA, as well as other species of ants. There were significant differences in the abundance of AWA, BHA, CPA, and other ant species foraging at the baits (F (3,36) = 5.43; P = 0.002) and (F (3,36) = 11.69; P < 0.0001) at Bagamoyo and Mkuranga, respectively, in 2010. The mean abundances of AWA, BHA, CPA, and ‘others’ were 66.6, 24.6, 35.0, and 59.5 %, respectively, at Bagamoyo in 2010. A similar trend was observed in 2011. The abundance of AWA was significantly negatively correlated with BHA (r (39) = −0.30; P < 0.0001) and CPA (r (39) = −0.18; P = 0.01) at Bagamoyo in 2010. A similar trend was also observed at Mkuranga. The abundance of AWA was therefore negatively affected by the presence of the two dominant ants, BHA and CPA, which may hinder the effectiveness of AWA to control sap-sucking pests in cashew. Therefore, suppression of BHA and CPA should be emphasized for effective control of the sap-sucking pests using AWA.

Foraging behavior and Preferences for Alternative Supplementary Feeds by the African Weaver Ant, Oecophylla longinoda Latreille (Hymenoptera, Formicidae)

Weaver ants, Oecophylla spp, are effective predators that control a wide range of insect pests in multiple crops when maintained at high population. Supplementary feeding, particularly during reduced food availability is one of the management practices that maintain and boost weaver ants’ populations. Experiments were conducted between September and October 2013, January and February, 2014 to determine the type of food preferred by weaver ants, O. longinoda. Twenty colonies of O. longinoda were provided with four types of food to determine their feeding preferences. These include anchovy, chicken intestine, fish intestines and earthworms. We examined food preferred by ants based on weight of the food removed and activity of the ants on foods. Furthermore, we examined foraging behavior of ant workers on anchovy food (fresh-ground and dry-ground) in nine O. longinoda colonies. Thereafter, small and large particles of dried-ground anchovy were tested. The results showed that O. longinoda preferred anchovy to other foods provided. However, the results of Analytical Hierarchy Process showed that earthworm and fish intestine were the most accessible food types by farmers, as determined by availability, affordability and applicabil ity. We observed more ants on fresh-ground as opposed to dry anchovy; similarly, large particles were more easily removed than was the case with small particles. Thus, during reduced food availability, farmers in the study area should use earthworms and fish intestines feeds to supplement O. longinoda colonies. Fresh moist anchovy or dry anchovy of large particle sizes can be used where available.

Potential of Oecophylla longinoda Latreille (Hymenoptera: Formicidae) in managing major insect pests in organic cashew production systems

Cashew production in Tanzania is severely constrained by sucking insect pests such as the coreid coconut bugs (Pseudotheraptus wayi Brown), the mirid bugs, Helopeltis spp. and thrips spp. These pests damage flushing foliar and floral shoots as well as young cashew fruits and nuts. Farmers rely heavily on insecticides in controlling these pests and there are no suitable alternative control methods compatible with organic cashew production. Weaver ants, Oecophylla longinoda Latreille have for long been considered as effective biological control agents against sap-sucking pests of cashew, but studies on their effectiveness as compared to conventional insecticides had never been conducted. The current study evaluated the efficiency of O. longinoda as compared to the recommended conventional insecticide, lambda cyhalothrin (Karate®) in controlling major cashew insect pests and compared the resulting cashew yield. The damage caused by each pest was significantly lower (P 0.05) in the damage between O. longinoda and Karate® treated trees suggesting that the two treatments are equally effective. The difference in the damage levels was directly reflected in the mean cashew yield. The two season’s results showed an average yield increases of 58.2 and 60.7 % in the insecticide-treated and in the O. longinoda-protected trees, respectively, in relation to untreated control plots. Thus, O. longinoda can serve as an alternative to chemical insecticides in Tanzanian cashew protection.

Nuptial flights behavior of the African weaver ant, Oecophylla longinoda Latreille (Hymenoptera: Formicidae) and weather factors triggering flights

Weaver ants (Oecophylla spp.) are intensively studied in basic and applied contexts. Yet, little is known about their mating behavior. Knowledge on their reproductive strategy is a prerequisite to the basic understanding of their life history and may provide valuable information facilitating their use in integrated pest management (IPM) and protein production (entomophagy). Here, we report on the behavior displayed by O. longinoda in relation with their nuptial flights in Tanzania and test for environmental cues that may trigger the flights. Based on observations of 56 flights recorded over 2 years, we found that sexuals aggregate on nest surfaces prior to flights. We also found that flights took place during the raining season, and all flights took place in evenings just before sunset. Further to these, days with flights were associated with higher relative humidity and less sun shine compared to days without flights. Also, flights mainly took place around full moons. However, this correlation was based on a total of only five full moon phases and should, therefore, be interpreted with caution. The results also showed that flights were only significantly correlated with weather parameters during the early part of the mating season, the trend changed thereafter probably due to depletion of sexuals in the nests as the season progressed. This information improves our understanding of ant nuptial flights and offers a tool to improve forecasts of O. longinoda flights, enabling easier collection of mated queens to stock ant nurseries that supply ant colonies for IPM-programs.

Antagonistic Interactions between the African Weaver Ant Oecophylla longinoda and the Parasitoid Anagyrus pseudococci Potentially Limits Suppression of the Invasive Mealybug Rastrococcus iceryoides.

The ant Oecophylla longinoda Latreille forms a trophobiotic relationship with the invasive mealybug Rastrococus iceryoides Green and promotes the latter’s infestations to unacceptable levels in the presence of their natural enemies. In this regard, the antagonistic interactions between the ant and the parasitoid Anagyrus pseudococci Girault were assessed under laboratory conditions. The percentage of parasitism of R. iceryoides by A. pseudococci was significantly higher on “ant-excluded” treatments (86.6% ± 1.27%) compared to “ant-tended” treatments (51.4% ± 4.13%). The low female-biased sex-ratio observed in the “ant-tended” treatment can be attributed to ants’ interference during the oviposition phase, which disrupted parasitoids’ ability to fertilize eggs. The mean foraging time, host handling time and number of successful oviposition in “ant-excluded” treatment were significantly higher compared to “ant-tended” treatments. When ant workers were allowed access to sterilized sand grains, mummified and unmummified R. iceryoides, they selectively removed the mummified mealybugs, indicating that they recognized the mummies as potential foods (1.2 ± 0.46 to 7.8 ± 1.17 mummies at 10 min intervals for 2 h). Percentage emergence from mummified R. iceryoides removed by the ants was significantly lower compared to emergence from mummies not exposed to ants. Although, host seeking parasitoids frequently evaded attacks, some were killed by the foraging ant workers (2.0 ± 0.38 to 6.0 ± 0.88 at 10 min intervals for 2 h). These results suggest for the first time that the presence of O. longinoda has a detrimental effect on the abundance, reproductive success and possibly oviposition strategy of female parasitoids, which might be a delimiting factor in field conditions if both natural enemies are to be recommended for use within the same agro-ecosystem.

English

The red weaver ant, Oecophylla longinoda Latreille is a predator of many insect pests of tree crops and its presence in orchards is perceived to result in improved fruit quality. This study therefore sought to investigate farmers’ perception of O. longinoda as a biological control agent for insect pests of citrus and its effect on fruit quality. A questionnaire-based survey was first used to investigate farmers’ perception of O. longinoda in major citrus growing districts in Ghana. Field and laboratory experiments were also conducted to test the effect of the presence of the weaver ant at different densities on taste [total soluble solids (TSS), total acidity (TA) and juice volume (JV)]. The survey results showed that 56% of farmers regarded weaver ants as pests, while 40% considered them as beneficial insects. Seventy percent observed no difference in taste while 28% observed improvement in taste. With respect to fruit appearance, 42% of the respondents said O. longinoda had no effect on appearance while 50% reckoned that it negatively affected the appearance of citrus. Laboratory analyses of citrus fruits showed that O. longinoda had no significant effect on fruit qualities. The implications of these findings on the acceptance of O. longinoda by farmers and suggestions for overcoming the challenges of accepting this biological control agent are discussed. Key words: Farmers’ perception, predator, Oecophylla longinoda, orange, fruit quality.

Mating Behavior of the African Weaver Ant, Oecophylla longinoda(Latreille) (Hymenoptera: Formicidae)

Mating in most species of ants occurs during nuptial flights. In the African weaver ant, Oecophylla longinoda Latreille, mating has previously been hypothesized to take place within the nest before the nuptial flight. However, several researchers disagree with this supposition particularly with reference to the closely related species Oecopylla smaragdina (Fabricius) whose mating occur during nuptial flights. Understanding the mating strategy of O. longinoda is of importance for its successful application in biological control programs. We conducted field and screen house experiments during two mating seasons to determine whether the mating occur prior to the dispersal flight. We examined winged O. longinoda queens on the nest surface before taking flight, immediately after leaving the nest, up to twelve hours (12h) after leaving the nest and after settling naturally following the dispersal flights. Mating in captivity between different number of males and queens were also assessed. Only eggs produced by queens (N=65) collected after their natural settling hatched into larvae. No eggs hatched from any of the 527 winged queens that were collected prior to their dispersal flights and no mating attempts in captivity lead to viable offspring. Findings from the current study suggest that mating of O. longinoda queens take place during a nuptial flight and does not take place within the nest, as previously suggested.

Influence ofOecophylla longinodaLatreille, 1802 (Hymenoptera: Formicidae) on Mango Infestation byBactrocera dorsalis(Hendel) (Diptera: Tephritidae) in Relation to Senegalese Orchard Design and Management Practices

Damage caused by the fruit fly Bactrocera dorsalis (Hendel) (syn. B. invadens Drew, Tsuruta & White) (Diptera: Tephritidae) on mangoes in Senegal leads to production losses. A potential biological control agent against this pest is the weaver ant Oecophylla longinoda Latreille (Hymenoptera: Formicidae). Senegalese mango-based orchards present a diversity in design and management practices that can influence the abundance of these two species in orchards. In this study we evaluated i) the ability of the O. longinoda ant to limit B. dorsalis damage in Senegalese orchards, and ii) variations in population abundance for these two species depending on orchard design and management practices. The study was conducted in Senegal in the Niayes area and the Thies plateau. Fifteen orchards were sampled among three out of four kinds of orchards identified in this area: (1) ‘No-input mango diversified orchards’, (3) ‘Medium-input citrus-predominant orchards’ and (4) ‘Medium-input large mango- or citrus-predominant orchards’. In one of the orchards we measured infestation rates and numbers of fly pupae that developed from mangoes collected from trees (cv. Kent) ‘with’ and ‘without’ O. longinoda colonies over three harvesting periods (May, July and August) in 2013. The abundance of O. longinoda and B. dorsalis was measured for two months in the dry season and two others in the rainy season in the 15 orchards in 2012. The presence of O. longinoda on trees reduced the proportion of mangoes attacked by B. dorsalis as well as the number of pupae that developed from infested mangoes. The abundance of O. longinoda and B. dorsalis was negatively correlated. The abundance varied depending on the orchard design and management practices. O. longinoda abundance was greater in orchard types 1 and 3 than in type 4. Conversely, B. dorsalis abundance in the rainy season tended to be greater in orchard type 4 than in types 1 and 3. This study showed that O. longinoda is effective in limiting mango infestations by B. dorsalis. It also showed that the abundance of these two species was influenced by the orchard design and management practices. Therefore, using O. longinoda to control fruit flies is possible in Senegalese mango-based orchards by promoting weaver ant preservation.

Control of mango seed weevils (Sternochetus mangiferae) using the African Weaver Ant (Oecophylla longinoda Latreille) (Hymenoptera: Formicidae)

AbstractThe mango seed weevil, Sternochetus mangiferae (Fabricius), is among the major threats to mango production in Tanzania. Sternochetus mangiferae is primarily a quarantine pest whose presence inside the fruits restricts access to new foreign markets and leads to rejections of fruits destined for export. Management options for the pest have largely been dependent on field sanitation and application of synthetic insecticides with some success. Thus, more sustainable methods are needed to substitute insecticides, as this may also open up opportunities for organic markets. We conducted field experiments for two fruiting seasons in a mango plantation at Mlandizi, Kibaha district, along the coastal belt of Tanzania to evaluate and compare the effectiveness of the predaceous ant Oecophylla longinoda Latreille with foliar insecticidal sprays of Dudumida (70 WDG Imidacloprid) in controlling S. mangiferae. Mango seed weevil infestation was assessed fortnightly based on infestation marks on developing fruits starting eight weeks after fruit set to early ripening phase. Between 50 and 64 fruits were sampled, well labelled in jute bags, secured and transported to the laboratory at Kibaha Biological Control Unit (KBCU) for incubation at room temperature using rearing transparent containers. Two weeks later, the fruits were dissected and inspected for the presence of S. mangiferae developmental stages. Field and laboratory results indicated that fruits from trees that were occupied by O. longinoda and from those treated with insecticide showed significantly (P &lt; 0.0001) lower incidences and infestation rates by S. mangiferae than from untreated trees. Furthermore, there were no significant differences between the insecticide and the weaver ant treatments. We conclude that in our experiments, O. longinoda is an efficient biological control agent for a long‐term control programme and is comparable to insecticide (Dudumida) in suppressing S. mangiferae and may be used in Tanzanian mango plantations.

Efficacy of fish- and hydramethylnon-based baits for conservation of the African weaver ant Oecophylla longinoda (Hymenoptera: Formicidae) during cashew off-seasons in Tanzania

The efficacy of fish- and hydramethylnon-based baits for conservation of the African weaver ant (AWA)Oecophylla longinodaLatreille was evaluated at orchards in Bagamoyo and Mkuranga districts, Coast region of Tanzania, during the cashew off-seasons in 2011 and 2012. The baits were applied at monthly intervals; the dynamics of AWA were monitored by counting the number of leaf nests/tree and the colonization trails on main branches. The numbers of leaf nests recorded before baiting ranged between 3.5 and 5.3 and were not significantly different at both sites and in both seasons; after baiting, they ranged between 3.2 and 11.6 at Bagamoyo and between 3.0 and 10.2 at Mkuranga. The colonization of AWA trails recorded before baiting was also not significantly different at both sites and in both seasons and ranged between 37.9 and 50.0%; after baiting, this ranged between 35.9 and 75.1% at Bagamoyo and between 34.6 and 79.2% at Mkuranga. The provision of fish- and hydramethylnon-based baits can effectively contribute to the conservation of AWA during the cashew off-seasons. The fish-based bait is cheaper and more easily affordable by local farmers and can, therefore, be used as an alternative diet for AWA at this time.

Founding weaver ant queens (Oecophylla longinoda) increase production and nanitic worker size when adopting non-nestmate pupae.

Weaver ants (Oecophylla longinoda Latreille) are used commercially to control pest insects and for protein production. In this respect fast colony growth is desirable for managed colonies. Transplantation of non-nestmate pupae to incipient colonies has been shown to boost colony growth. Our objectives were to find the maximum number of pupae a founding queen can handle, and to measure the associated colony growth. Secondly, we tested if transplantation of pupae led to production of larger nanitic workers (defined as unusually small worker ants produced by founding queens in their first batch of offspring). Forty-five fertilized queens were divided into three treatments: 0 (control), 100 or 300 non-nestmate pupae transplanted to each colony. Pupae transplantation resulted in highly increased growth rates, as pupae were readily adopted by the queens and showed high proportions of surviving (mean = 76%). However, survival was significantly higher when 100 pupae were transplanted compared to transplantation of 300 pupae, indicating that queens were unable to handle 300 pupae adequately and that pupae require some amount of nursing. Nevertheless, within the 60-day experiment the transplantation of 300 pupae increased total colony size more than 10-fold whereas 100 pupae increased the size 5.6 fold, compared to control. This increase was due not only to the individuals added in the form of pupae but also to an increased per capita brood production by the resident queen, triggered by the adopted pupae. The size of hatching pupae produced by the resident queen also increased with the number of pupae transplanted, leading to larger nanitic workers in colonies adopting pupae. In conclusion, pupae transplantation may be used to produce larger colonies with larger worker ants and may thus reduce the time to produce weaver ant colonies for commercial purposes. This in turn may facilitate the implementation of the use of weaver ants.

Facilitating the use of alternative capsid control methods towards sustainable production of organic cocoa in Ghana

Cocoa (Theobroma cacao L.) is an important foreign exchange earner for Ghana. However, production is constrained by a high incidence of pests and diseases. Based on farmers' needs, this study focused on the control of capsids, mainly Sahlbergella singularis Haglund and Distantiella theobroma (Distant) (both Hemiptera: Miridae). Annual crop loss caused by capsids is estimated at 25 - 30%. To control capsids, formal research recommends application of synthetic insecticides four times between August and December. However, farmers hardly adopt this recommendation, which they consider unsuitable for their conditions and context. Three alternative control methods were tested with farmers: mass trapping, using sex pheromones; applying crude aqueous neem Azadirachta indica A. Juss. (Meliaceae) seed extract (ANSE) and using the predatory ant Oecophylla longinoda Latreille (Hymenoptera: Formicidae) as a biological control agent. Contrary to most previous reports, studies on temporal distribution of cocoa capsids indicated that the population peaked in March. ANSE was effective against capsids and other cocoa insect pests and did not affect the predatory ant. When O. longinoda occurred in high numbers, capsid incidence was low. Shade did not influence ant or capsid abundance significantly. ANSE caused 100% mortality of capsids in cage and 79 -88% in field experiments. The sex pheromone was as effective as ANSE or ants in suppressing capsids. All the three methods were effective and compatible; hence, they can be used in an integrated pest management strategy for cocoa, including organic production in Ghana.