International Journal of Marine Science 2015, Vol.5, No.57: 1-5
1
A Letter Open Access
Effect of twelve species of marine phytoplankton on larval survival and
development of the mosquito
Culex quinquefasciatus
Sushanth V. Rai , Rajashekhar M.
Department of Biosciences, Mangalore University, Mangalagangothri – 574 199, Karnataka, India
Corresponding author email
International Journal of Marine Science, 2015, Vol.5, No.57 doi
Received: 29 Jul, 2015
Accepted: 28 Aug, 2015
Published: 28 Sep., 2015
Copyright
©
2015 Sushanth, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is properly cited.
Sushanth V. Rai, Rajashekhar M., 2015, Effect of twelve species of marine phytoplankton on larval survival and development of the mosquito
Culex
quinquefasciatus
, International Journal of Marine Science, 5(57): 1-5
Abstract
In the present study, effect of twelve species of marine phytoplankton on the growth and development of mosquito larvae
of
Culex quinquefasciatus
was investigated. Among the 12 phytoplankton isolates, mortality of the larvae was observed in the
suspensions of cyanobacteria species namely,
Nostoc
commune
,
Phormidium
corium
,
P. tenue
and planktonic green alga
Nannochloropsis oceanica
.
N.
oceanica
showed effective larvicidal activity with 100% mortality of larvae. The development of
larvae fed with phytoplankton cells was delayed compared to the control with respect to the first pupation period. The wing length of
the adults emerged from the larvae fed with phytoplankton cells were shorter than control and those of adults emerged from
Chroococcus turgidus, Oscillatoria geminata, Chaetoceros calcitrans
and
Skeletonema costatum
treatment were similar in size to
that of control. The present study showed that some species may serve as nutritious food for mosquito larvae, whereas others
especially
N.
oceanica
has the potential to be used as natural pesticide to control mosquito
C. quinquefasciatus
.
Keywords
Larvicidal activity;
Nannochloropsis oceanica;
Probit analysis; Indigestible phytoplankton
1 Introduction
Control of disease-bearing vectors relies heavily on
the extensive and intensive use of chemical insecticides.
These chemicals are to certain extent quite successful
in controlling the diseases concerned. In view of some
of the side effects of chemical agents used in vector
control, environmental friendly approaches and the
use of biological control agents have gained much
importance. In the case of mosquitoes, phytoplankton
deserves particular attention (Clements, 1992).
Some species of phytoplankton provide nutritious
food for mosquito larvae, whereas others produce
allelochemicals that are toxic to mosquitoes at different
stages (Kiviranta and Abdel-Hameed, 1994; Gross,
2003; Legrand et al., 2003; Graneli and Hansen, 2006;
Rey et al., 2009). It is common in nature for mosquito
larvae to die before completing their development
because they are poisoned by phytoplankton toxins or
they starve to death while feeding on phytoplankton
that are indigestible (Ahmad et al., 2001; Marten,
2007). Mosquito indigestible phytoplankton have
good field characteristics as a biological control agent
against mosquitoes because they are naturally present
in the habitats of mosquito larvae and are able to
multiply and persist in these habitats. Another major
advantage of phytoplankton for mosquito control is
the expectation that mosquitoes will not evolve resistance
to their use (Ahmad et al., 2001). The objective of the
present study is to investigate the effect of twelve
species of marine phytoplankton on the survival and
development of mosquito larvae of
Culex quin
-quefasciatus
.
2 Materials and Methods
2.1 Isolation and maintenance of phytoplankton
cultures
Twelve phytoplankton species including nine cyano
bacteria (
Chroococcus turgidus
,
Lyngbya confervoides
,
Nostoc commune
,
Oscillatoria fremyii
,
O. geminata
,
O.
sancta
,
Phormidium corium
,
P. tenue
and
Spirulina
major
), two diatoms (
Chaetoceros calcitrans
and
Skeletonema costatum
) and the planktonic green alga
(
Nannochloropsis oceanica
) were isolated from rocks,
puddles and sea water of Arabian Sea coast (West
coast of India).
The filamentous cyanobacteria were isolated by micr
-opipette method, whereas unicellular cyanobacterium
(
Chroococcus turgidus
), diatoms and planktonic green
alga were isolated by agar plate method (Andersen,
2005). The cultures were microscopically examined
