This document provides a literature review on guppies (Poecilia reticulata) and Lake Sebu, Philippines. It discusses the taxonomy, morphology, behavior, habitat, and feeding of guppies. It also describes the location, climate, population, industries, and festivals of Lake Sebu. Finally, it reviews the SHAPE software which is used to analyze biological shapes through elliptic Fourier descriptors and principal component analysis.

1. REVIEW OF RELATED LITERATURE
Jordan P. Arroyo Jr.*
, Mythel Faith T. Solis#
, Khesed Adonai E. Garcia
Mindanao State University
9500 General Santos City, Philippines
e-mail: j_arroyo0422@yahoo.com*
sis_mythel@yahoo.com#
I. GUPPY (Poecilia reticulata)
TAXONOMY
Kingdom: Animalia
Phylum: Chordata
Class: Actinoptergii (Ray-finned Fish)
Order: Cyprinodontiformes (Tooth-carp)
Family: Poeciliidae (Livebearer)
Genus: Poecilia
Species: Poecilia reticulata
Guppies (Peters, 1860), commonly known as million fish, or more likely to be
called as rainbow fish are small, brackish or fresh-water dwellers (Nelson, 1994) in
which males have maximum lengths of 3.5 cm., and females having 6 cm. (Froese and
Daniel, 2010). Females are pale olive-colored with transparent fins and are typically
larger than males. Males on the other hand are polychromatic, which means they have a
variation of color combinations especially in their sides and fins. These colors are usually
red, orange, yellow, blue, and green with white and black patches. With these variable
colorations, no two males are identical in terms of pigment patterns (Meffe and Snelson,
1989). Guppies are remarkably to have distinct and marked sexual dimorphism
(Ringuelet and Aramburu, 1967). The Poeciliidae family has about 200 species coming
from 16 genera (Parenti, 1981). Guppies are neotropical species which are natives of
Northwestern South America (Bisazza, 1993), and was then introduced in many countries
in Asia, and other continents to be used as an effective controllers of mosquitoes and/or
as an ornamental fish for aquariums.
Guppies are benthopalgic – live on or in the sediment at the bottom of a sea, lake,
or deep river. They inhabit waters ranging from springs to ponds and estuaries and are
tolerant to wide salinity values letting them to inhabit freshwater, brackish and epipelagic
layer of marine habitats. They have also became popular aquarium species for the reason
that they are able to survive warm water temperatures from 22-24˚C (Froese and Daniel,
2010) even up to 32˚C (Gibson, 1954) but not more than 36˚C (Arai et. al., 1963). As
omnivorous individuals, they feed mainly on small insects, particularly the mosquitoes,
zooplanktons, algae, and detritus (Froese and Daniel, 2010). However, guppies have also
been observed eating native fishes’ eggs, and are occasionally exhibiting cannibalism by
eating their own young (Shoemaker, 1944). By this, they also threaten native fishes and
act as vectors for other parasites (Invasive Species Specialist Group, 2006).
(A. Webb, M. Maughan, and M. Knott, 2007)

2. On studies made for fish population distribution in deteriorated water systems,
guppies were reported as indicators of waters in poor conditions (Araújo, 1983), that is
why they are considered to as interest of study, representing one of the most significant
model in evolutionary ecology due to its quick response to natural selection (Reznick and
Bryga 1987, Reznick et al. 1990, Reznick et al. 1997, Magurran 2005). Taking also to
consideration that guppies are found incredibly in varied habitats, they also encompass a
wide range of groupings to adapt comparative level of predation (Haskins et al. 1961).
In terms of feeding behavior, males spend 15-30% of their time feeding, while
females spend about 45-73% (Dassault and Kramer, 1981). Their diet consists mainly of
zooplankton, small aquatic insects and larvae, detritus (Arthington, 1989), and sometimes
fish eggs (Edredge, 2000). When feeding, particularly on benthic algae, P. reticulata
bites rapidly by teeth to loosen algae in scraping motion. As the guppy approaches food,
it moves its whole body in a forward-downward motion with a closed mouth leaving the
food vertically (Magurran, 2005). This behavior was observed by Dassault and Kramer
and has concluded that the pecking occurs at time intervals of 0.55 seconds, the jaw
movement at 0.17 seconds and substrate contact at 0.03 seconds and ingesting algae of as
much as 25% daily when feeding continuously.
P. reticulata have also developed a social organization wherein they build schools
which are active at daytime (diurnal), disperse at night time and reassemble at morning
time (Croft et. al., 2003) and perform polygamy, where males mate with several females
in succession. Though, limited studies were done in their population, some studies
showed that they create small shoals of 2 to 20 individuals, which can be entirely males,
females, or mixed sex, that allows direct contact every 14 seconds. Through this, guppies
can live undisturbed together with other fish species and upon introduction to new
populations can join new shoals without resistance from other members.
Upon mating season, a male follows a female until it stops or slows. Once the
females notices the him, he will arch laterally in S-shape, and quivers stiffly for a short
period of time with closed caudal fins or minimal display of fins in vertical axis of few
millimeters, or may just jump away (Magurran, 2005). Males also darken their black
spots and horizontal line changes color patterns, and sometimes leading away female in a
less crowded area. Studies also showed that males which are large and or having brighter
orange spots in their bodies are more likely to be selected by females (Houde 1987;
Karino and Shinjo 2004; Karino and Haijima 2004; Karino et al. 2005). Another study
also suggested that predation pressure was also an evident selection factor in male colour
variation (Miller et. al., 2006), and influenced mate selection (Reynolds and Gross,
1992). Females can store sperms for later fertilization and may produce young every four
weeks. Pregnant females are recognizable by black triangle between anal and pelvic fins.
After a gestation period of four to six weeks females give birth to 20-40 live young. No
parental care is exercised and parents may even prey on their young.

3. II. LAKE SEBU
The Municipality of Lake Sebu is a part of the South Cotabato Province located in
its southwestern part, approximately 40 kilometers away from Koronadal City, and is
approximately 6 hours away from Cotabato City. It sits in an altitude of 300 m. with
its lowest point to be 450 m. and highest point of about 1 972 m. Its total land area is
89 138 ha. or 891.38 square kilometers which is divided into different land uses:
Built-Up, 446 ha.; Agriculture, 22 492 ha.; Pasture, 9 139 ha.; Forest, 54 902 ha.;
Misc. 2 148 ha.
It was created on November 11, 1982, under Batas Pambansa Blg. 249, and was
considered the “Center of Eco-Cultural Tourism” of South Cotabato. Lake Sebu has
19 barangays and has a total human population count of 60 401 (NSO Survey, 2007).
Accounts to this count are the different ethnic groups namely Ilongos comprising
32%, T’boli/Ethnic Tribes covering 58%, Maguindanaoans making up 2%, Cebuanos
constituting 6%, and 2% for others.
Lake Sebu is a first class in terms of income classification for its major industry
which is farming, or inland farming – cottage industries, rattan furniture. Its major
products include rice, corn, handicrafts (tinalak), forest products, wildlife resources,
and tilapia.
Lake Sebu also has a lake named after its municipality, which is a beautiful bowl
of water, that is surrounded by hills and forests, with some bamboo trees growing
alongside. In the lake are spokes of bamboo fish traps and dug-out canoe floating on
the surface. The climate of Lake Sebu is a fourth type for the reason that the rainfall is
evenly meted out all year round. Its average temperature is analogous to that of
Tagaytay City which temperature varies between 20˚C to 25˚C. Lake Sebu’s
desiccated season usually occurs between months of March and April and rain
showers typically happen during afternoons of February and May.
Lake Sebu is the largest lake among the four lake systems found near the
municipality, with an area of 452 hectares. Other lakes, like Lake Lahit is only 24
hectares, while Lake Seloton is 48 hectares, and Lake Bacdulong, or Sebu Udi is only
24 hectares.
Besides, Lake Sebu has also its festival called the Helubong Festival happens
every 9th
to 11th
day of November, wherein the Municupality of Lake Sebu celebrates
its foundation anniversary, reflecting the unique cultural identity and ethnicity of the
province. Another is the Lemlunay Festival which is celebrated every month of
September.

4. III. SHAPE ver. 1.3
SHAPE is a software developed by Hiroyoshi Iwata (Ph.D) of Tokyo Japan used
for general application of the method based on Elliptic Fourier Descriptors (EFDs)
(Kuhl and Giardina, 1982). SHAPE works by extracting the contour shape from a
full-color bitmap image and then delineates the contour shape with the EFDs, and
finally performs the principal component analysis of the EFDs for summing up the
shape formation. On the other hand, Elliptic Fourier Descriptors (EFDs) (Kuhl and
Giardina, 1982) delineates any type of shape with a closed two-dimensional contour,
and have been effectively applied to the evaluation of various biological shapes in
animals and plants. SHAPE contains four programs named ChainCoder, Chc2Nef,
PrinComp and PrinPrint for processing digital images, obtaining EFDs, performing
principal component analysis and visualizing shape variations explained by the
principal components, respectively.
Image Analysis Program or ChainCoder extracts the contour of objects from an
image file and records them as chaincode (Freeman 1974). Chaincode is a coding
system for describing geometrical information about contours in numbers from 0 to 7.
ChainCoder converts a full color image to a binary (black and white color) image,
reduces noise, traces the contours of objects and describes the contour information as
chaincode. ChainCoder outputs a chaincode file, which is analyzed by the program
Chc2Nef.
Elliptic Fourier Transformation Program or Chc2Nef calculates the normalized
EFDs from the chain code information. The normalized EFDs are calculated in
accordance with the procedures suggested by Kuhl and Giardina (1982). Chc2Nef can
perform two types of normalization. One is based on the first harmonic ellipse that
corresponds to the first Fourier approximation to the contour information. The size
and orientation of the contour is standardized in accordance with the size and
alignment of the major axis of the ellipse. The starting point for tracing the contour is
also standardized with respect to the major axis. Another normalization is based on
the point of the contour farthest from the center (i.e. the longest radius). This
normalization is performed in accordance with the direction and absolute size of the
vector from the center to the farthest point. In Chc2Nef, the normalization can be also
performed manually, if desired.
Principal Component Analysis Program or PrinComp performs a principal
component analysis of the normalized EFDs derived by Chc2Nef. When a contour
shape is described in the first 20 harmonics of Fourier coefficients, the number of
normalized EFD coefficients becomes large (77 or 80). However, principal
component analysis can efficiently summarize the information contained in these
coefficients (Rohlf and Archie 1984). The principal component analysis conducted by
PrinComp is based on the variancecovariance matrix of the coefficients and not on
the correlation matrix, because coefficients with small variance and covariance values
are generally not important for explaining the observed morphological variations.

5. Contour Visualization Program or PrinPrint visualizes the shape variation
accounted for by each principal component, using the procedure proposed by Furuta
et al. (1998). First, the coefficients of the elliptic Fourier descriptors are calculated,
letting the score for a particular principal component be equal to the mean plus or
minus two times the standard deviation (i.e. the square root of the eigenvalue of the
component), and the scores of the remaining components be zero. Then the contour
shape on each condition can be reconstructed from the coefficients by inverse Fourier
transformation. This visualization is helpful for understanding the morphological
mean of the variation evaluated by each principal component. Reconstructed contours
are easily printed with a standard printer.

6. REFERENCES
Araújo, FG.*, Peixoto, MG., Pinto, BCT. and Teixeira, TP. 2009. Distribution of guppies
Poecilia reticulata (Peters, 1860) and Phalloceros caudimaculatus (Hensel, 1868) along
a pollutedstretch of the Paraíba do Sul River, Brazil. Laboratório de Ecologia de Peixes,
Universidade Federal Rural do Rio de Janeiro – UFRRJ,Antiga Rodovia Rio – SP, Km
47, CEP 23851-970, Seropédica, RJ, Brazil.
Arthington A.H., 1989. Diet of Gambusia affinis holbrooki, Xiphophorus helleri, X. maculata
and Poecilia reticulata (Pices: Poeciliidae) in streams in southeastern Queensland,
Australia. Asian Fisheries Science 2: 193-212.
Croft, D. P., Arrowsmith, B. J., Bielby, J., Skinner, K., White, E, Couzin, I. D. et al. 2003.
Mechanisms underlying shoal composition in the Trinidadian guppy, Poecilia reticulata.
Oikos 100: 429-438
David, K. M. 2001. The Online Guide to the Animals in Trinidad and Tobago – Poecilia
reticulata.
Dussault, G. V. & Kramer D. L. 1981 Food and feeding behaviour of the guppy, Poecilia
reticulata (Pisces: Poeciliidae), Can. J. Zool. 59: 684-701.
Froese, R. & Daniel, P. 2010. Poecilia reticulata.
Froese R. and Pauly D. (Eds.), 2007. FishBase [online] version (02/2014). Available from:
www.fishbase.org {Accessed February 2014}.
Iwata, H., 2006. SHAPE ver. 1.3 – A Software Package For Quantotatove Evaluation of
Biological Shapes Based on Elliptic Fourier Descriptors. National Agricultural Research
Organization.
Karino K. and Shinjo S., 2004. Female mate preference based on male orange spot patterns in the
feral guppy Poecilia reticulata in Japan.
Houde, A. E. 1997. Sex, colour, and mate choice in guppies. Princeton University Press,
Princeton, N. J. Invasive Species Specialist Group, 2006. Poecilia reticulata (fish).
Houde A.E., 1987. Mate choice based upon naturally occurring color-pattern variation in a
guppy population. Evolution 41: 1-10.
Magurran, A. E. 2005. Evolutionary ecology: the Trinidad guppy. Oxford University Press,
Oxford, London.
Meffe, G. K. & Snelson, F. F. (1989). Ecology and evolution of livebearing fishes (Poeciliidae).
Prentice Hall, Englewood Cliffs, N. J.

7. Reznick, D., Buckwalter, G., Groff, J., and Elder, D. 2001a. The evolution of senescence in
natural populations of guppies (Poecilia reticulata): a comparative approach.
Experimental Gerontology. 36: 791-812.
Shoemaker, H. H. 1944. A laboratory study of fish populations. Trans. Amer. Fish. Soc. 74: 350-
359
Webb, A., Maughan M., and Knott M. 2007. Pet Fish Profiles: Poecilia Reticulata – Guppies. ©
ACTFR, James Cook University.
Zandona, E. 2010. The Trophic Ecology of Guppies (Poecilia reticulata) From The Streams of
Trinidad.