Flight Of Alates Research Articles

Accumulated precipitation and air density are linked to termite (Blattodea) flight synchronism in a Seasonally Dry Tropical Forest in north‐eastern Brazil

AbstractTermite dispersal flights (Blattodea: Termitoidae) are influenced by several factors that are intrinsic and extrinsic to colonies and vary according to the environment and target species. This study aimed to evaluate the main characteristics of the dispersal flights of a termite community and the environmental variables related to these flights in a Seasonally Dry Tropical Forest, situated in the semiarid region of north‐eastern Brazil. The alates were collected with trays placed on the ground. Sampling was carried out over a year, with weekly trap reviews. Flight peaks started in February; i.e. these events were more frequent and alates from all species were captured. The trays were checked daily for 40 days during this period. A principal coordinate analysis was performed to determine the response variables and, after that, a generalised linear model was performed to analyse the relationship between these variables and environmental variations. Alates of 37 species were captured and the community flight pattern proved to be synchronised and highly temporally concentrated, regardless of family, subfamily or even genera. The daily sampling analysis showed that 97% of species flights occurred between the 13th and 33rd days following the start of the 40 days of daily revisions. The number of flight occurrences and species composition were significantly influenced by the accumulated precipitation over 72 h and air density. The latter variable was evaluated for the first time in this type of study. The high synchronism between species may be related to the brief period in which arid and semiarid ecosystems have the correct conditions for alate flights, which is different to alate flight occurrence in tropical rainforests, where the environmental conditions usually allow termites to fly throughout the entire year.

Relative occurrence of the family Kalotermitidae (Isoptera) under different termite sampling methods

The termite family Kalotermitidae constitutes a wood-nesting termite family that accounts for about 15% of all extant termite species. In recent decades, field studies have been carried out to assess termite diversity in various wooded habitats and geographic locations. Three sampling methods have been favored expert, transect, and alate light-trap surveys. Expert collecting is not spatially quantifiable but relies on field personnel to recognize and sample termite niches. The transect method aims to standardize and quantify termite abundance and diversity. Light trapping is a passive method for sampling nocturnal alate flights. We compared our expert survey results and results of published sampling methods for their proportional yields of kalotermitid versus non-kalotermitid encounters. Using an odds ratio statistic, we found that worldwide, there is about a 50.6-fold greater likelihood of encountering a kalotermitid sample versus a non-kalotermitid using the expert survey method and a 15.3-fold greater likelihood using alate trapping than using the transect method. There is about a 3.3 -fold greater likelihood of collecting a kalotermitid specimen versus a non-kalotermitid sample using the expert survey method than using the alate trap method. Transect studies in which only termite species diversity was reported gave similar low Kalotermitidae yields. We propose that multiple biases in sampling methodology include tools, time constraints, habitat type, geographical location, topographical conditions, and human traits account for the divergent outcomes in sampling the abundance and diversity of Kalotermitidae compared to other termite families.

Dynamics of sex ratio, fresh weight and nutrient contents at five developmental stages of alates in the subterranean termite Reticulitermes chinensis

Sex ratio, fresh weight and nutrient contents were examined at five developmental stages of alates in the subterranean termite Reticulitermes chinensis Snyder, including sixth-instar nymphs, callow alates, dark alates, flying alates and dealates. The results showed that the sex ratio of callow alates and dark alates was highly female biased, but there were no significant differences in the percentage of females and males at sixth-instar nymphs, flying alates, and dealates. The fresh weights of alates declined with the developmental stages, suggesting a dynamic process in which the termites continue to shrink and harden. Meanwhile, the weights of female alates were significantly higher than weights of male alates in all five stages. There were no significant differences in the protein titers of the five developmental stages of alates. Flying alates were observed to have the highest triglyceride level, but a low glucose titer. This suggested that the main energy for flight of alates is provided by the breakdown of triglyceride reserves. Alates regardless of developmental stages, workers and soldiers had no significant differences in the cholesterol titers for the two extraction methods. Interestingly, there was a significantly negative linear correlation between the titer of glucose and the titer of triglyceride in both female alates and male alates during the five developmental stages, suggesting that the indirect mutual transformation between glucose and triglyceride might occur in the energy metabolism of all alates in R. chinensis.

Ants under the conditions of an extremely hot summer

Specific features of ant behavior during the extremely hot summer of 2010 were studied, as well as the aftereffects of this season on simple and complex family units of ants in 2011–2012. Simultaneous studies were carried out in southern taiga (Moscow Province, Verkhnaya Klyazma myrmecological protected area) and northern taiga (Arkhangelsk Province, Pinezhskii Nature Reserve). Ants of the genus Formica responded to the extreme heat by (1) changing their foraging patterns; (2) redesigning their nests; (3) rearranging the spatial and functional structure of the colonies. They switched to a bimodal activity pattern with maxima in the morning and in the evening and a prolonged daytime intermission. Along ant roads, there were underground pavilions with dense roofs built of conifer needles and soil. Covers of the same kind appeared over root aphid colonies. The most radical improvement was the construction of a battery of brood chambers underneath the mound. The soil excavated was used for strengthening the mound and restricting the convective heat exchange between the brood chambers and the external environment. The anthill surface was covered with a smooth crusted layer of soil and fine plant debris particles, which protected the nest from the inflow of hot air from without. A portion of the inhabitants of large nests moved to newly built extensions and auxiliary nests. It was only active, non-damaged colonies that could afford these measures and thus survive the heat with minimal loss. Depressed colonies lost the major part of their brood during this time. Furthermore, small secondary colonies that emerged as the result of destructive activity of animals also failed to reassemble due to the summer heat of 2010. The months of heat were followed by a long rainy and cool period, and the colonies that had already been depressed faced critical conditions for preparing for winter. The ants were unable to accumulate lipid reserves sufficient for spring nest heating and rearing of sexuals and workers, which turned out to be an important aftereffect of the 2010 season the following year. Two first generations of workers were absent in almost all the nests. Mass oviposition in F. aquilonia commenced only late in May 2011, whereas the flight of alates did not occur at all because alates of this species are only reared in spring. Consequently, the F. aquilonia colonies had not recovered even by the end of 2012. In F. lugubris and F. polyctena, species that rear sexuals twice a year, there was only late-season alate flight, and yet it allowed their colonies to replenish the pool of ovipositing females and restore the initial colony size by the end of 2012. Other ants, represented by Lasius niger and Myrmica rubra, also modified their nests and foraging patterns during the period of heat. M. rubra suffered the most, so that its abundance and activity remained very low in 2011 as well. Only L. niger, which remained practically unscathed by the heat, successfully completed its annual cycle in 2010. Therefore, one of the 2010 year’s results was a drastic shift in the ratio of nests built by the abovementioned species in favor of L. niger.

Field Evaluation of Potential Control Strategies Against the Invasive Eastern Subterranean Termite (Isoptera: Rhinotermitidae) in Chile

Four different termite control strategies consisting of two soil treatments with cypermethrin and fipronil and two bait treatments with hexaflumuron and sulfluramid were evaluated for their efficacy and potential for controlling the invasive eastern subterranean termite, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae), in Quillota and Valparaíso, Chile. Monitoring stations were installed at all sites to measure the overall termite activity next to and at distances up to 30 m away from infested structures, most being 3–5 m. Foraging activity was extremely seasonal with the maximum consumption rates occurring from January to April. Termite foraging activity was low from July to September. After treatments in January 2003, there was a significant decrease in wood consumption, percentage of active stations, and numbers of termites in traps for the first 6 mo with hexaflumuron baits. No significant change in R. flavipes foraging activity was observed on wood consumption and percentage of active stations for sulfluramid bait or cypermethrin and fipronil soils treatments. The seasonal pattern of foraging activity remained unchanged for all treatments in 2004 and 2005, except structures baited with hexaflumuron. Feeding activity at the monitors in the area surrounding the hexaflumuron baits declined to 0 after January 2004. Alate flights occurred in ≈38% of the structures treated with cypermethrin and sulfluramid bait in 2003 and in ≈40% of the structures treated with cypermethrin, fipronil, and sulfluramid bait in 2004. Sulfluramid baits and cypermethrin soil treatments did not have any impact within a 15-m radius of the structures. Soils treatments of fipronil and cypermethrin prevented termites access in 75% of the homes. The number of active monitoring stations only declined within 2 m of the fipronil-treated zone. Hexaflumuron exhibited a reduction in activity for at least a 15-m radius.

Field Evaluation of Potential Control Strategies Against the Invasive Eastern Subterranean Termite (Isoptera: Rhinotermitidae) in Chile

Four different termite control strategies consisting of two soil treatments with cypermethrin and fipronil and two bait treatments with hexaflumuron and sulfluramid were evaluated for their efficacy and potential for controlling the invasive eastern subterranean termite, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae), in Quillota and Valparaiso, Chile. Monitoring stations were installed at all sites to measure the overall termite activity next to and at distances up to 30 m away from infested structures, most being 3-5 m. Foraging activity was extremely seasonal with the maximum consumption rates occurring from January to April. Termite foraging activity was low from July to September. After treatments in January 2003, there was a significant decrease in wood consumption, percentage of active stations, and numbers of termites in traps for the first 6 mo with hexaflumuron baits. No significant change in R. flavipes foraging activity was observed on wood consumption and percentage of active stations for sulfluramid bait or cypermethrin and fipronil soils treatments. The seasonal pattern of foraging activity remained unchanged for all treatments in 2004 and 2005, except structures baited with hexaflumuron. Feeding activity at the monitors in the area surrounding the hexaflumuron baits declined to 0 after January 2004. Alate flights occurred in approximately 38% of the structures treated with cypermethrin and sulfluramid bait in 2003 and in approximately 40% of the structures treated with cypermethrin, fipronil, and sulfluramid bait in 2004. Sulfluramid baits and cypermethrin soil treatments did not have any impact within a 15-m radius of the structures. Soils treatments of fipronil and cypermethrin prevented termites access in 75% of the homes. The number of active monitoring stations only declined within 2 m of the fipronil-treated zone. Hexaflumuron exhibited a reduction in activity for at least a 15-m radius.

The reproductive flight phenology of a neotropical ant assemblage

Summary1. Alate flights reflect an ant colony's investment in sexual reproduction and dispersal yet little is known about community‐wide patterns of alate phenology. Two Malaise traps (for 2 years) and two light traps (for 1 year) were used to explore the flight phenologies of 22 common neotropical species from Barro Colorado Island, Panama.2. The traps caught 23 182 individuals and 286 species/morphospecies. The two trap methods shared only 18 species. Samples also differed in sexual composition: light trap samples were 80% female, Malaise trap samples were 2.6% female.3. Of 22 common species, all but one flew over half the year, with about half flying every month of the year. These data, combined with a literature review, suggest a latitudinal gradient in alate flight season: one north temperate assemblage (42°N) averaged 1.6 lunar months per species. The ever‐warm tropical year provides a larger flight window that allows a diversity of phenologies, from continuous to strongly pulsed.4. Rainfall was correlated with alate flights in one‐third of the species. Quantile regression suggested that high weekly rainfall was necessary but not sufficient to produce alate flights in about a quarter of the species.5. By decreasing the number of nests releasing alates on a given day, long flight seasons may lower the probability of finding a mate. At the same time, long flight seasons may increase the opportunity of finding vacant nest sites. High population densities and high incidence of nest disturbance in this community may ameliorate the first cost while enhancing the second benefit.

Longevity, fecundity, change in degree of gravidity and lipid content with adult age, and lipid utilisation during tethered flight of alates of the corn leaf aphid, Rhopalosiphum maidis

SUMMARYThe longevity, daily fecundity, degree of gravidity and lipid content of alates of varied ages, and lipid utilisation during sustained tethered flight of the corn leaf aphid, Rhopalosiphum maidis, were studied. Alates had a mean longevity of 9.7 days and a mean fecundity of 14.9 nymphs. A significant increase in the lipid content of alates before emerging as adults was observed. Newly emerged and half‐day‐old alates had more lipid reserve and embryos than 1‐, 2‐, 4‐, 8‐, and 16‐day‐old specimens. The lipid content of alates decreased significantly with age. The alates' degree of gravidity and lipid content had a low but significant correlation.Half‐ to 1‐day‐old alates flew readily and could fly for much longer durations than 2‐ and 4‐day‐old. Eight‐day‐old alates were not capable of flight. R. maidis utilised lipid during prolonged tethered flight. Our data suggest that there is a threshold point when alates cease utilising stored lipid as the energy source and start utilising non‐lipid sources as flight fuel energy.

Prey attraction as a possible function of bioluminescence in the larvae of Pyrearinus termitilluminans (Coleoptera: Elateridae)

Elaterid beetle larvae. Pyrearinus termitilluminans (sp.n., Costa, 1982.) live in termite mounds in central Brazil. Each larva produces light in the segment immediately behind its head. Larvae were observed to luminesce only during the first weeks of the rainy season, the same times as the ant and termite alate flights. Alates, apparently attracted to P. termitilluminans larval lights, serve as an important food source for the larvae. The prey-catching and food-storing behavior and the phenomenon of bioluminescence are apparently an evolutionary response by P. termitilluminans larvae to a short, rich pulse of food. Prey attraction as a probable cause for luminescence has been suggested only twice before.

Seasonal Variation in Caste Proportions of Field Colonies of Reticulitermes flavipes (Kollar) 1

When seasonal variation of caste proportions was quantified in “nests” of the subterranean termite Reticulitermes flavipes (Kollar), workers comprised the most abundant caste, with a 2-year average of 84.0% of the individuals. Larvae comprised 8.7%, nymphs 5.0%, adult soldiers 2.1%, and presoldiers and neotenic reproductives 0.1% each. Alates and eggs were found infrequently. Caste proportions changed significantly with season, apparently varying according to the reproductive cycle. Larvae are most abundant in the summer and least abundant in the winter. Soldiers were most abundant immediately preceding alate flights, and least abundant immediately thereafter. Nymphs showed two peaks of abundance (early fall and early summer). Workers were most abundant during the spring and summer months.

Nutrient cycling by the subterranean termite Gnathamitermes tubiformans in a Chihuahuan desert ecosystem.

We estimated the density of subterranean termites Gnathamitermes tubiformans at 800,000 · ha-1 for a standing crop biomass of 2 kg · ha-1 Predation losses were estimated to be 5,73 kg · ha-1 · yr-1 representing the major release of nutrients from termites to surficial soil layers. Nutrient fluxes from termites to predators amounted to 410g N·ha-1·yr-1, 33 g S · ha-1 · yr-1 and 19 g P · ha-1 · yr-1. These fluxes account for 8% of the litter N, 1.5% of the litter P and 2.9% of the litter S. The termites fixed an estimated 66 g · ha-1 · yr-1 atmospheric N and returned an estimated 100 g · ha-1 · yr-1 in the surface gallery carton. Since losses of elements from subterannean termites were greater than standing crops, we estimated an annual turnover of N at 3.5 times per year, P of 2.5 times per year, and S of 2.5 per times per year.Since surface foraging, predation and alate flights are pulse regulated by rainfall, nutrient flows through subterranean termites are episodic and releases of nutrients accumulated in termite biomass preceeds or is coincident with productivity "pulses" of some shallow rooted plants. We propose that subterranean termites are important as regulators in desert nutrient cycles.

Nest and soil populations of Trinervitermes spp. with particular reference to T. geminatus (Wasmann), (Isoptera), in Southern Guinea savanna near Mokwa, Nigeria.

Nest and soil populations of Trinervitermes spp. were estimated on grazed secondary savanna woodland near Mokwa cattle ranch and on primary savanna woodland, 6 km from the ranch. Nest populations were estimated by obtaining a relationship between size of nest and the number of termites in the nest and using the relationship to estimate populations in measured nests within the study area.Mound populations of T. geminatus, by far the most abundant species, were 222 m-2 at a mound density of 232 ha-1 at the ranch, and 225 m-2 at a mound density of 175 ha-1 on primary savanna woodland. The mound population at the ranch represented a fresh weight biomass of 1.089 g m-2. Changes in abundance of the mound population of T. geminatus were correlated with breeding and foraging cycles. Maximum numbers (388 m-2, 2.03 g m-2) in August/September were reduced by the flight of alates and loss of foragers to predators; thereafter, the population continued to decrease (126 m-2, 0.57 g m-2) until the cessation of foraging in April/May and numbers of larvae and nymphs began to increase. Soil and mound sampling in primary and secondary savanna showed that although T. geminatus is a mound inhabiting species, two thirds of the mound plus soil population was outside the mounds giving a total population of 737 m-2 (3.08 g m-2). Alate production was estimated at 15.5 m-2 (0.19 g m-2) and neuter production at 367 m-2 (1.66 g m-2); production/biomass ratio was 1.0 T. togoensis (total population of 21 m-2) and T. occidentalis (200 m-2) had 90-96% of the total numbers outside the mounds, indicating that these two species were primarily subterranean.

Epidemiology of potato leaf roll virus in the Fraser River delta of British Columbia

The spread of potato leaf roll virus (PLRV) and the resulting phloem necrosis in the tubers has been a limiting factor in the production of the Netted Gem (Russet Burbank) variety in southwestern British Columbia, Canada. Steckling sugar beets are an important overwintering host for nymphs and adults of the green peach aphid,Myzus persicae (Sulzer). By June, aphids are widely disseminated to the florets and new leaves of sugar beet and other hosts, including potato. Colonies with alates are produced on summer hosts which are not treated with insecticides. The peak of the flight of alates from the colonies on the summer hosts occurs during the first half of August. Those alates that were produced on PLRV-infected potato and which travel to other potatoes transmit the virus as soon as they feed. By the end of August, the sugar beet seed crops and the early and mid-season potato crops have been defoliated or harvested. Thus many colonies ofM. persicae are destroyed and the threat of PLRV spread diminishes. Crop and weed plants which serve as overwintering hosts become infested during late summer with alate aphids. Their offspring survive the winter in numbers which are determined by the weather and survival of host plants.