Antimicrobial property of male accessory gland secretions in
coconut beetle, Oryctes rhinoceros
V. S. Josekumar 1 , B. Jayachandran Nair 2 , O. G. Indusree 3
and Leenamma Joseph 4
1 . V. S. J OSE K UM AR, Re se arc h D i vi s io n, Dep ar t me n t o f Zo o lo g y, M ar
Iva n io s Co l le ge , T hi r u v an a nt hap u ra m, Ker ala , I nd i a 6 9 5 0 1 5 .
2 . B . J AY AC H AN D R AN N AI R, Fo r es t Dep ar t me nt , Go v t. o f Ker al a, I nd i a.
3 . O. G. I N DU S REE , Dep ar t me n t
T hir u va na n t hap ur a m, Ke r ala, I nd ia 6 9 5 0 1 5 .
of
Zo o lo g y,
Mar
I va n io s
C o lle g e,
4 . LEE N AMM A J O SEP H, Dep ar t me n t o f Zo o l o g y & E n vi ro n me n tal S cie nc e,
St. J o h n s Co lle g e, An c h al, Ker a la, I nd ia .
Bioactive molecules with antibacterial properties are being
identified from various animal sources. Glandular secretions
from many insect species exhibit antimicrobial action (Gillot,
2003., Joseph et al., 2009), are good sources of antimicrobial
peptides. These substances provide the innate immunity
mechanism in insects assisting their reproductive success (Lung
et al., 2001). Many antibacterial peptides are clinically important
as antibiotic (Hancock and Chappel, 1999). The present study
report antimicrobial properties in the body secretions of the
coconut beetle, Oryctes rhinoceros. Male accessory reproductive
gland secretions (ARG) and haemolymph fluid (HF) from virgin
male beetle were screened for antibacterial activity using disc
diffusion sensitivity test. Five bacterial st rains viz., Bacillus
subtilis, Klebsiella pneumoniae, Salmonella typhi, Proteus
vulgaris and Pseudomonas aeruginosa were tested against ARG
and haemolymph fluid along with a reference antibiotic
cyclofloxacin. 50 ul secretions and 20 ug cyclofloxacin were
loaded individually on sterile discs placed on a bacteria seeded
petriplates and incubated at 30 O C in BOD incubator.
Antimicrobial action was identified as clear inhibitory zone
developed around the loaded disc. Antimicrobial action of ARG
and HF was identified against B.subtilis, K. pneumonia and S.
typhi. However, P. vulgaris and P. aeruginosa were insensitive
to both AG and HF of this insect. The experiment was repeated
with virgin female and mated female insect reproductive
secretions against Bacillus subtilis. Mated female spermatheca
and accessory gland secretions exhibited antibacterial action in
B. subtilis while the virgin female secretions failed to
demonstrate antimicrobial activity. This suggests that the
antimicrobial property of the male accessory gland is being
transferred to female during mating. This support the view that
male secretions simultaneously provide antimicrobial protection
during reproductive process along with sperm contribution s to
female. The study also highlights the importance of insect
sources to identify clinically important antimicrobial peptides.
Keywords: antibacterial; accessory reproductive gland;
haemolymph; Oryctes rhinoceros.
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