MSc

The study entitled “Seasonal incidence of predatory wasp (Vespa spp.) in
Indian bee apiaries and evaluation of bait traps” was carried out in the Department
of Agricultural Entomology, College of Agriculture, Vellayani during 2015-17.
The objective was to study the seasonal incidence of Vespa spp. in Indian honey
bee apiaries, assessment of its predatory potential and evaluation of bait traps
against the wasp.
The observations were recorded throughout the three
beekeeping seasons (lean season, brood rearing season and honey flow season) of
the year 2016-17 in the apiaries at Nedumangad, Vilappilshala, Vellayani and
Balaramapuram.
The incidence of honey bee pests’ viz. wax moth, spiders, wasps, ants,
lizard, honey buzzard and monkey, their symptoms and mode of attack were
documented. The damage by larvae of wax moth (Galleria mellonella Linnaeus)
was observed as galleries and faecal pellets of excreta in the brood comb. The
spiders predating on bees were identified as Argiope anasuja Thorell, Hersilia
savigyni Lucas and Thomisus lobosus Tikader. The predatory wasp collected
from the apiaries was identified as Vespa tropica Linnaeus. Among the ants, the
weaver ant, Oecophylla smaragdina Fabricius and godzilla ant, Camponotus
compressus Fabricius predated on the bees whereas, the yellow crazy ant,
Anoplolepis gracilipes Smith fed on the hive honey. Cent per cent infestation by
ants were observed in the apiaries which was followed by the wasps (59.86 %)
and wax moth (34.87 %). The infestation by the spiders, lizard (Hemidactylus
sp.), honey buzzard and monkey (Macaca radiata Geoffroy) was found to be the
least.
Though the predatory wasp was observed in the apiary premises
throughout the day, the peak period was found to be from 0930 to 1030 hour
(26 visits hr-1), which corresponds to the active foraging hours of honey bees.
Maximum wasp incidence was observed during the month of November
(181 visits). Of the four locations, the highest wasp incidence (251 visits) was
recorded at Nedumangad which may be due the hilly areas and thick vegetation in
that region.
Studies on the seasonal incidence of V. tropica revealed that
significantly higher wasp population was observed during the brood rearing
season than the lean season and honey flow season. Correlation studies of the
wasp incidence with the weather data (monthly basis) showed a non-significant
relationship with all the weather parameters (temperature, relative humidity and
rainfall).
Studies on the predatory potential of wasp revealed that the bees were
found predated by the wasps only for five weeks i.e., from 41st week to 44th week
and also in 48th week. Out of the 52 bees predated by the wasp, maximum
predation (18 Nos.) was recorded in 44th week (31st October, 2016 to 6th
November, 2016). Observations on the predatory strategy of wasps showed four
distinct behaviour viz., arrival, approach, attack and predation. The bees failed to
show defense response to the injured wasp placed at the hive entrance and
continued their usual foraging behaviour. On facing persistent attack by the
wasps, the bees ceased foraging activities, buzzed around and guarded the hive
entrance. The frustrated bees were also found to engulf the wasp in a ball of bees,
rendering it immovable.
Evaluation of bait traps using carbohydrate based - fermented pineapple +
molasses (4:1) (150 g) and protein based - beef (50 g), chicken (50 g), fish (50 g)
along with untreated control (water) revealed that no traps were efficient in
trapping the wasps. More number of bees (22 Nos.) were trapped in carbohydrate
based trap (fermented pineapple + molasses trap), rather than the wasps (0.5
Nos.). Other insects were also trapped.
The predation of honey bees by the wasp recorded in the apiaries was
59.86 per cent with peak incidence during the month of November. Significantly
higher wasp population was observed during the brood rearing season (September
- December) of honey bees. Maximum predation of bees (18 Nos.) was observed
in the 44th week. Since no bait traps were found efficient in trapping the wasps, a
new method has to be developed against the wasp.