Printer Friendly

Determination of developmental modules of the fore and hind wing of the peacock pansy Junonia almanac Linnaeus 1758 (Nymphalidae: Lepidoptera) using modularity and integration software.

INTRODUCTION

Lepidopteran wings exhibit great diversity in design and in colour, with the pattern of almost every species being distinct from all others. Patterns on the dorsal and ventral wing surfaces are frequently quite dissimilar and those of the forewing and hindwing are also different. In addition some species are genetically colour-polymorphic while others show seasonal polyphenism or phenotypic plasticity, by which individuals with similar genotype can develop different patterns in response to rearing conditions [1]. The development of the wing pattern elements is to some extent integrated in overall wing development meaning the butterfly wings experience a multitude of different natural and sexual selection pressures either simultaneously or sequentially, which will select for a particular wing size and shape in response to the environmental and ecological conditions experienced [2]. The elements have identities that can be traced from species to species, and typically across genera and families. Because of this, it is possible to recognize homologies among pattern elements and to study their evolution and [3]. Because it displays diversification, it is an ideal material to study morphological integration and the evolution of developmental independence [4].

In this study, the morphometric data of the fore- and hind wing of the Peacock Pansy butterfly (J. almana) was examined to determine how many modules are found between the sexes and are they morphologically integrated. This was tested using Modularity and Integration (MINT) analysis tool [3]. The patterns of variational modularity and integration are assessed by testing alternative a priori models, each of which hypothesizes a distinct modular structure caused by specific functional or developmental mechanisms [3].

MATERIALS AND METHODS

Samples were collected from 2 provinces in Mindanao: Lanaodel Norte, and Misamis Occidental, using a lightweight, long handled sweep net. The collected butterflies were then placed delicately in a white paper envelope to prevent damages. Identification of the individual were based on the following: In males, they are smaller which means less weight to carry, greater strength to weight ratio for better agility, they are more brightly colored, more pointed forewings (flight aerodynamics, built for speed, chase and evasion) and they have skinner abdomens (no eggs) which is opposite to the females.

The fore and hind wing were carefully detached from the thorax using a dissecting needle or scalpel and mounted on two glass slides using forceps and sealed together using invisible tape and then labeled. The mounted wings were scanned using a Hewlett-Packard Jacket 2400 scanner in a 1200bpi resolution. The images was then cropped, sorted according to wing type and orientation and then saved. A total of 195 points was used for outlining the shape of wings as well as their major vein pattern. TPSDig2 software [5] was used in digitally outlining the fore and hind wing. The outlined data was then converted to landmark points (XY) using TPS util [6] and then loaded to MINT (Modularity and Integration Analysis Tool). Different hypothesis (Tables 1-2a, 2b) were formulated to test and determine whether the entire wing of J. almanais a single module or whether the compartments are independent units.

The models were tested using the Modularity and Integration Tool version 1.5 [3] to test for variation modularity to evaluate whether a proposed model or hypothesis is good enough to explain variation in the data set. The models are outlined using tpsDig tool. The process generated a total of 14 models of variational modularity in the shape data, including the null model that assumes that no modularity exist (Fig. 2-3). The points representing the modules are converted to landmark. Each model represents a hypothesis.

Resulting P-values and [[gamma].sup.*] values depict associations within integrated sets of traits or variational module. A low (<0.05) P value, closer to zero, indicates that the models generated are significantly different from the observed data. The model is thus a poor fit and must be rejected. However, P-values greater than 0.05, (P>0.05) and approaching 1, correspond to low [[gamma].sup.*] values. This indicates a high degree of similarity between the proposed model and the observed data and thus, the proposed model is accepted [3].

RESULTS AND DISCUSSION

The best fit models of the left fore wing of J. almanaare model 6 and 4 for female and male, respectively while in the right fore wing is model 4. The best fit models of the left and hind wing of J. almana is model 4 for the female and male. The two competing models are both accepted with P-values greater than 0.05 and being the best fit models, both have the lowest y*-value. Figure 4, Model 4 showed the best fit of majority. Model 4 of the fore and hind wing has 5 distinct modules (1) the anterior margin of the wing is bounded by the 1st radial vein (2) the 1st radial vein is bounded by the 2nd radial vein (3) the 2nd radial vein is bounded by the 2nd cubitus vein (4) the 2nd cubitus vein is bounded by the anal vein (5) the anal vein is bounded by the posterior margin of the wing. The result is supported by the Gamma values presented in Table 8. The P-value for the null hypothesis that the data are no more different from this model than expected by chance is 1 based on Wishart/Monte Carlo test with 1000 replicates.

The results shows (Table 4) that the left fore wing have different ranks of best fit model while on the right showed the same ranks. The same is seen on the hind wings. The left hind wing showed different ranks of best fit models while on the right showed the same ranks. This difference in the best fit model indicates factors caused by modularity and sexual dimorphism. There is covariation because the compartmentalization process creates modules that are overlap spatially, even if the process responsible for it is independent. Sexual dimorphism evolved due to independent effects of genetic variation on both sexes. Sex specific gene regulations occur as a result of selection during male and female towards different reproductive optima. Changes in gene regulations and expressions may have further consequences for the sexual fitness of one or both sexes [7].

The results also confirmed a number of studies suggesting that insect wings are divided into compartments and that their modules served as autonomous unit of morphological variation and each of compartments are a separate developmental module [4, 8, 9, 10, 11] These compartments may correspond to distinct cell lineages and domains of gene expression [12, 13]. This aspect of variational modularity describes the condition of varying in modular fashion and results from the operation of several unique evolutionary processes that operate on phenotypic development [14].

Conclusion and recommendation:

This study was conducted to determine the modularity and integration in the fore- and hind wings between sexes of the Peacock Pansy Butterfly, J. almana. and is limited only on the samples collected from 2 provinces in Mindanao: Lanao del Norte and Misamis Occidental. A total of 14 models of variational modularity in the shape data; including the null model that assumes that no modularity exist, was conducted and tested to determine how many modules are found between the sexes of the fore and hind wing of J. almana.

Results show various ranks of best fit models indicating presence of sexual dimorphism and variations caused by factors of modularity. Sexual dimorphism caused by sex specific gene regulations and variational modularity associated with the genetic material variation and environmental condition influence.

REFERENCES

[1] Brakefield P.M. and V. French, 1993. Butterfly Wing Patterns: Developmental Mechanisms an Evolutionary Change. ActaBiotheoretica, 41: 447-468.

[2] Breuker, C.J., M. Gibbs, S. Van Dongen, T. Merekx and H. Van Dyck, 2010. The Use of Geometric Morphometrics in Studying Butterfly Wings in an Evolutionary Ecological Context. Morphometrics for Nonmorphometricians, Lecture Notes in Earth 271 Sciences 124, DOI 10.1007/978-3-540-95853-6-12.

[3] Marquez, E.J., 2008. Mint: Modularity and Integration Analysis tool for morphometric data. Version 1.0b (compiled 09/07/08). Mammals Division, University of Michigan Museum of Zoology.

[4] Beldade, P., K. Kopps and P.M. Brakefield, 2002. Modularity, Individuality, and Evo-devo in Butterfly wings. Proceedings of the National Academy of Sciences of the United States of America (PNAS), 99: 14262-12367.

[5] Rohlf, F.J., 2006. tpsDig version 2.10.Department of Ecology and Evolution. State University of New York at Stony Brook. New York.

[6] Rohlf, F.J., 2009. TPSUtil version 1.44. Department of Ecology and Evolution. State University of New York at Stony Brook. New York.

[7] Allen, C.E., B.J. Zwaan and P.M. Brakefield, 2011. Evolution of Sexual Dimorphism in the Lepidoptera. The Annual Review of Entomology, 56: 445-64.

[8] Klingenberg, C.P., A.V. Badyaev, S.M. Sowry and N.J. Beckwith, 2001. Inferring Developmental Modularity from Morphological Integration: Analysis of Individual Variation and Asymmetry in Bumblebee Wings. The American Naturalist, Vol.157, No.1.

[9] Tabugo, S.R., M.A. Torres and C.G. Demayo, 2011. Determination of Developmental Modules and Conservatism in the Fore- and Hindwings of two Species of Dragonflies, Orthetrum Sabina and Neurothemisramburii. Int. J. Argic. Biol., 13: 541-546.

[10] Torres, M.A.J., L.A. Adamat, M.M.E. Manting, S.R.M. Tabugo, R.C. Joshi, L. Sebastian, A.T. Barrion and C.G. Demayo, 2010. Developmental modules defining the shape of the forewing of Scotinopharacoarctata. Egypt. Acad. J. biolog. Sci., 3(1): 105-112.

[11] Zimmerman, E., A. Palsson and G. Gibson, 2000. Quantitative trait loci affecting components of wing shape in Drosophila melanogaster. Genetics, 155: 671-683.

[12] Garcia-Bellido, A., P. Ripoll and G. Morata, 1973. Developmental Compartmentalisation of the wing disk of Drosophila. Nature (London), 245: 251-25.

[13] Lawrence, P.A., 1992. The making of a fly: the genetics of animal design. Blackwell scientific, Oxford, UK.

[14] Galliguez, E.M., M.A.J. Torres, J.G. Gorospe, M.M.E. Manting and C.G. Demayo, 2009. Modularity and Integration in the Shape of the Shell of Vivipara angularis Muller (Architaenioglossa: Vivaparidae). Journal of Nature Studies, ISSN, pp: 1655-3179.

Vanessa Mae C. Tumang, Mark Anthony J. T orres and Cesar G. Demayo

Department of Biological Sciences, MSU-Iligan Institute of Technology, Iligan City, Philippines

ARTICLE INFO

Article history:

Received 23 June 2015

Accepted 25 July 2015

Available online 30 August 2015

Corresponding Author: Vanessa Mae C. Tumang, MSU-Iligan Institute of Technology, Department of Biological Sciences, 9200, Iligan City, Philippines. Tel: +639152706462 E-mail: harpy04@gmail.com

Table 1. Developmental modules of the fore wings based
on the wing venation pattern of J. almanaL.

Model    Modules                  Descriptions

H1      no modules          Null model, there is no
                     compartmentalization within the wings
H2          1           Every compartment serves as one
H3          5            between the anterior margin of
                        the wing and the 2nd radial vein
                          between the 2nd radial vein
                            and the 4th radial vein
                          between the 4th radial vein
                            and the 2nd medial vein
                          between the 2nd medial vein
                            and the 2nd cubitus vein
                        between the 2nd cubitus vein and
                        the posterior margin of the wing
H4          5            between the anterior margin of
                       the wing and the 1 st radial vein
                          between the 1 st radial vein
                            and the 2nd radial vein
                          between the 2nd radial vein
                            and the 2nd cubitus vein
                            between the 2nd cubitus
                             vein and the anal vein
                         between the anal vein and the
                          posterior margin of the wing
H5          3            between the anterior margin of
                        the wing and the 2nd radial vein
                          between the 2nd radial vein
                            and the 2nd cubitus vein
                        between the 2nd cubitus vein and
                        the posterior margin of the wing
H6          4            between the anterior margin of
                       the wing and the 1 st radial vein
                            between the 1 st radial
                          vein and the 4th radial vein
                             between the 4th radial
                         vein and the 1 st cubitus vein
                         between the 1 st cubitus vein
                      and the posterior margin of the wing
H7          2            between the anterior margin of
                       the wing and the 1 st medial vein
                          between the 1 st medial vein
                      and the posterior margin of the wing

Table 2a: Developmental modules of the hind wings based
on the wing venation pattern of J. almanaL.

Models    Modules                  Descriptions

H1       no modules          Null model, there is no
                      compartmentalization within the wings
H2           1           Every compartment serves as one
H3           5            between the anterior margin of
                         the wing and the 2nd radial vein

Table 2b: Developmental modules of the hind wings based
on the wing venation pattern of J. almanaL.

Models   Modules               Descriptions

H3                        between the 2nd radial
                       vein and the 1st medial vein
                          between the 1st medial
                      vein and the 1st cubitus vein
                         between the 1 st cubitus
                          vein and the anal vein
                      between the anal vein and the
                       posterior margin of the wing
H4       5          between the anterior margin of the
                      wing and the 1 st radial vein
                       between the 1 st radial vein
                         and the 2nd radial vein
                       between the 2nd radial vein
                         and the 2nd cubitus vein
                         between the 2nd cubitus
                          vein and the anal vein
                      between the anal vein and the
                       posterior margin of the wing
H5       3          between the anterior margin of the
                       wing and the 2nd radial vein
                       between the 2nd radial vein
                          and 1 st cubitus vein
                     between the 2nd cubitus vein and
                     the posterior margin of the wing
H6       4            between the anterior margin of
                     the wing and the 2nd radial vein
                       between the 2nd radial vein
                         and the 1st medial vein
                       between the 1st medial vein
                         and the 1st cubitus vein
                    between the 1 st cubitus vein and
                     the posterior margin of the wing
H7       4             between the anterior margin
                   of the wing and the 2nd radial vein
                          between the 2nd radial
                       vein and the 1st medial vein
                       between the 1 st medial vein
                         and the 2nd cubitus vein
                     between the 2nd cubitus vein and
                     the posterior margin of the wing

Table 3: Best Fit Model for fore
and hind wing of J. almana L.

           Sex

           Female   Male

Forewing

Left         6       4
Right        4       4

Hindwing

Left         4       4
Right        4       4

Table 4: Top three best fit models for the left and right
Fore- and Hind wings of male and female J. almana L.

Forewing

Female

Wing       Model   Rank   Gamma Value   P-Value

Left         6      1       0.14474        1
             4      2       0.15322        1
             5      3       0.1591         1

Wing       Model   Rank   Gamma Value   P-Value

Right        4      1       0.15565        1
             5      2       0.18479        1
             6      3       0.21456        1

Hindwing

Female

Wing       Model   Rank   Gamma Value   P-Value

Left         4      1       0.22931        1
             5      2       0.24772        1
             7      3       0.30427        1

Wing       Model   Rank   Gamma Value   P-Value

Right        4      1       0.1832         1
             5      2       0.2055         1
             3      3       0.29725        1

Male

Wing       Model   Rank   Gamma Value   P-Value

Left         4      1       0.12489        1
             6      2       0.13051        1
             5      3       0.14091        1

Wing       Model   Rank   Gamma Value   P-Value

Right        4      1       0.20129        1
             5      2       0.23775        1
             6      3       0.2729       0.999

Male

Wing       Model   Rank   Gamma Value   P-Value

Left         4      1       0.2378         1
             5      2       0.25848        1
             3      3       0.34111        1

Wing       Model   Rank   Gamma Value   P-Value

Right        4      1       0.39882        1
             5      2       0.41106        1
             3      3       0.42942      0.849
COPYRIGHT 2015 American-Eurasian Network for Scientific Information
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2015 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Tumang, Vanessa Mae C.; Torres, Mark Anthony J.T.; Demayo, Cesar G.
Publication:Advances in Environmental Biology
Article Type:Report
Date:Aug 1, 2015
Words:2543
Previous Article:Fluctuating asymmetry and developmental instability in the wings of Neurothemis terminata as bioindicator of stress.
Next Article:Species composition and gut content analysis of fishes in Mandulog River system, Iligan City.
Topics:

Terms of use | Privacy policy | Copyright © 2019 Farlex, Inc. | Feedback | For webmasters