54 VV. Vidhu and DA. Evans
Keywords
Altruism · Formic acid · Oecophylla smaragdinaimmobility or lack of coordination in movements in ants after biting. The
observed hyper-proteinemia in ants within 30 min was evidenced by ad-
ditional bands in electrophorogram.Introduction
The Asian arboreal weaver ant is a dominant,
highly aggressive and predaceous insect. They
form the most elaborate communicative organi-
zation in the insect world. They form complex
organizations through their simple intelligence
to emerge as an elaborate social structure. These
ants are living as a polymorphic colony possess-
ing industrious workers, reproductive males,
females and developing stages (Holldobler and
Wilson 1977 ). The worker ants are known for
their painful irritating bite and so they are called
as the ‘living pesticides’ utilized in biological
control of the world earliest record in China
(Konishi and Ito 1973 ; Huang and Yang 1987 ).
The workers aggressively defend territory and
prey on any organism, which can be over pow-
ered by them with sharp mandibles and a simulta-
neous spray of formic acid (FA) from abdominal
glands. Observation in the field and bioassay in
the laboratory revealed that FA plays an impor-
tant role in the life of these worker ants. Biting
the enemy or intruder and going on biting until
death is a peculiar feature seen in this particu-
lar species of worker ants and the biochemistry
behind this altruistic behaviour also form the
subject matter of this chapter.
Material and Methods
The ant nests were collected in glass jar from the
garden plants from the University College Cam-
pus, Trivandrum with minimum disturbance and
were anesthetized using chloroform. The colony
individuals were separated, weighed and the FA
content was estimated (Colowick and Kaplan
1963 ). The FA content of colony individuals and
head, thorax and abdomen of worker ants was
estimated. The FA content at different time inter-
vals of 24 h such as morning, afternoon, evening
and night (7 am, 1 pm, 6 pm and 1 1 pm) was also
estimated. Periodicity studies were conducted
during sunny days of April and May 2010. The
ants were disturbed for 15 min by gentle tap-
ping on the nests and after that FA content was
estimated. The major workers were allowed to
bite at a particular site on the body for more than
30 min or till death and after that, FA content
was estimated. Standard biochemical techniques
were used for the quantitative estimation of pro-
tein (Lowry et al. 1951 ), free amino acids (FAA)
(Spies 1957 ), glycogen (Carrot et al. 1956 ), lac-
tic acid (Colowick and Kaplan 1963 ) and acetyl-
choline (Ach; Augustinson 1957 ). The activities
of aspartate aminotransferase (AsAT) and ala-
nine aminotransferase (AlAT) were estimated as
described by Reitman and Frankel ( 1957 ). The
content of glucose, urea and uric acid were esti-
mated by enzyme kits (Span Diagnostics, India
Ltd.).
Abdomen of major workers were dipped in
ice-cold distilled water for 2 min, after that fine
surgical needle was inserted in to the tip of ab-
domen, the glands were exposed by gentle pull
and viewed under dissection microscope. Photos
of poison gland and Dufour’s were taken using
Sony cyber-shot 4× optical zoom camera. The
protein profile of the head and thorax of worker
ants, before and after 30 min of continuous bite
was done by standard electrophoretic techniques
(SDS PAGE). Statistical analysis was done as
described by Daniel ( 2006 ).