Vol. No. June 1993 12 Nolul. odonalol.. 4, I, pp. 1-20, I,

Dragonfly distribution along New Calabar River, near Port Har-

court, Nigeria (Anisoptera)

O.C. Umeozor

Department of Zoology, University of Port Harcourt, Box 384, Uniport Post Office, Port Harcourt,

Nigeria

Abstract – 13 months larvae col- located in the rainforest During were area, tropical and pro-

then salt lected bimonthly at 6 sample sites and reared vides a gradualtransition from fresh to water.

to the adults. Chloride and Biochemical Oxygen It has a high diversity of aquatic insects. This

Demand (BOD) were measured monthly at each study was therefore undertaken to determine the

sample site during 12 months in order to assess odonate larvae distribution along the New Cala-

bar Port Harcourt. The is the influence of these factors on odon. distribu- River, near study also

tion the river. Atotal of collec- intended baseline information along 11 spp. were to provide some

ted (I -8 spp. per site). Regressionanalysis indica- on dragonfly species found in the area.

ted that odon. distribution was significantly

affected by Chloride and BOD. accounting for Material and methods

32.4 and 48.3%, resp. ofthe variation in distribu- Dragonfly distribution along the New Calabar

tion. As each variable increased, the number of River, near Port Harcourt was investigated for

decreased. 13 months 1989-November spp. per site (November 1990) by

bimonthly collecting larvae from 6 sample sites

Introduction along the river (Fig. 1), and rearing them to

In the Afrotropical region, dragonfly studies fall adults. Also, two variables. Chloride and Bioche-

into those restricted Demand index two major areas: to one or mical Oxygen (BOD) (an ofpollu-

measured each two species (e.g. GAMBLES, 1966, 1970, 1971, tion), were monthly at sample site

1972; L1NDLEY. 1970; PARR & PARR, 1972, for a period of 12 months (December 1989-No-

1974; PARR, 1974) and those restricted to taxo- vember 1990) and related to dragonfly distribu-

collection and identification adults the These factors cho- nomy, of tion along river. two were

(PINHEY. 1961a, 1961b, 1962, 1971; DUMONT, sen because transition from fresh to salt water is

1977, 1978). Such studies contribute immensely gradual in the area, and water pollution, espe-

to the understandingof regional fauna, but some cially from petroleumproducts, is fairly common.

other aspects ofinterest are neglected.For exam- The collection of larvae was restricted to the

concerned with the collection and lotic and done from ple. studies margin was a canoe using a

of adults do informa- the identification not provide dip net. During collection, net was submerged

in under while tion on larvae, breeding sites and breeding pe- water aquatic weeds, and, holding

riods of adults. Studies restricted to one or two the handle of the net with one hand, the weeds

with species are of limited application because the were held and shaken the other hand in order

the of diversity of dragonflies in Africa is enormous. to dislodge larvae clinging to roots weeds

Within the in- into the This 50 times Afrotropical region, published net. process was repealed

is The larvae formation on dragonflies unevenly distributed. per sample site per sample period.

For example, there isno information on the lower were taken to the University of Port Harcourt

Niger delta. Yet this delta is a complex ecological campus’for rearing. Notul. Vol. No. June odonatol.. 4, I, pp. 1-20, I, 1993 13

For each lar- Method sample site, only representative Argcmometric was used to measure

The vae were reared after each sample period for the Chloride (APHA, 1985). Azide Modification more common species; all the less common lar- Method was used to determine the initial and

in vae were reared. Rearing was done a small final Dissolved Oxygen (DO) (APHA, 1985).

house. Larvae from each site The final DO determined after 5 of open-air sample was days were reared separately using water collected from incubation. BOD was computed from the diffe- the sample sites. The purpose of the rearing was rence between initial and final DO. Regression for the used whether Chloride and easier identification of species, most of analysis was to test which known in the adult final larval BOD distribution are only or significantly affected dragonfly stage. Rearing involved placing 3-5 larvae in a along the river. Both variables were treated as clear plastic container (11 cm long, 6 cm wide, independent variables, while the number of drag-

16 A 17 site the cm deep) half-filled with water. cm long onfly species per sample was dependent

2 wide flat stick variable. by cm was placed diagonally within each container for the insects to crawl out

and The end of the container Results discussion emerge. open was and

covered held A 11 with nylon-screen, in place with a total of species was collected. The number rubber band. Water in the container was changed of species per sample site ranged from 1 to 8

The larvae fed chironomid larvae col- daily. were (Tab. I). Regression analysis indicated that drag-

lected within the Cam- distribution the from gutters University onfly along river was signifi-

the pus. Upon emergence, adults were killed with cantly affected by Chloride and BOD. Based on ethyl acetate and dried in a desiccator containing Rsquare (Tab. 1), Chloride and BOD accounted

anhydrous calcium chloride pellets. These adults for 32.4 and48.3 percent of the variation in distri-

later S.J. Brooks The of the were identified by (British bution, respectively. slope regression

R.W. Museum, Natural History) and equation ((3) (Tab. I) indicated that there was a

Garrison (Asuza, California, USA). negative relationship between each variable and

Water samples for the determination of Chlo- the number of species per sample site. In other

ride and BOD were collected from each sample words, as each variable increased, the number of

site tides. These the when site decreased. duringhigh are periods species per sample

salt flows into coastal inlet The collected site listed in water waters. Species per sample are

Table II. The highest number of spe-

cies was collected from Elele Ali-

mini, followed by Rumuji and then

Oduoha, while only onespecies was

collected from Rumuoparani (Tab.

II. Fig. 1).

Rumuoparani is the transition

zone between fresh and mixohaline

indicated the (brackish) water as by

mangrove forest: mangrove thrives

in mixohaline and salt water envi-

ronments (Fig. I). Three species,

Chalcostephiaflavifrons, Gomphus

and li- sp., Urothemis edwardsi, are

mited in distribution from Elele Ali-

mini to Oduoha (Tab. II, Fig. I).

Trithemis stictica was collected

the from Elele Ali- throughout year

mini to Oduoha and from Isiodu and

Choba only in January 1990 (Tab. Fig. 1. Map of a section of the lower Niger delta, showing II, Fig. 1). This indicates that the New Calabar River and the six sample sites. Vol. 14 Notul. odonalol.. 4. No. I. pp. 1-20, June I, 1993

I - and Demand Table Effect of Chloride Biochemical Oxygen (BOD) on dragonfly distribution along New Calabar River, near Port Harcourt, Nigeria

Regression

Sample site: Elcle Alimini Rumuji Oduoha Isiodu Choba Rumuoparani analysis

2 (Slope R [ß|)

No. of species/ sample sile 8 7 5 2 2 1

Mean Chloride

(mg/1)/ sample site 2.43 2.55 2.58 5.56 11.06 66.07 -0.569 0.324

Mean BOD

(mg/l )/ sample site 1.43 0.82 1.13 1.68 2.60 2.35 -0.695 0.483

Table II - Distribution of New Calabar Port dragonflies along River, near Harcourt, Nigeria

SiteSile Species Period

Alimini - Elele Alimini Gomphus sp,sp.

C the Chalcostephiahalcostephia flavifrons throughout year

Hadrothemis infesta -

Olpogastra lugubrisluguhris -

Orthetrum - Orthetrum sp.sp.

Oxythemis gamblesiyarnhlesi -

Trithemis sticticasta tica throughout the year

the Urothemis edwardsi throughout the yearyear

Rumuji Gomphus sp. -

Macromia - sp.

ChalcostephiaChalt ostephiaßavifronsflavifrons throughout the year

CyanothemisCyanothcmis simpsoni Nov. 1989,1989, Nov. 1990

Sympetrum navasi Sept. & Nov. 1990

Trithemis sticticatica the Trithemis sta throughout year

edw ardsi the Urothemis edwardsi throughout the year

- Oduoha Gomphus sp.

the Chalcostephia flavifrons throughout the year

Sympetrum navasi throughout the year

Trithemis sticticasta tica throughout the year

Urothemis edwardsiedw ardsi throughout the year

the Isiodu Sympetrum navasi throughout year

TrithemisTrithemis stasticticatica Jan. 1990

navasi the Choba Sympetrum throughout the year

Trithemis siústicticatica Jan. 1990

Macromia Nov. 1989,1989, Nov. 1990 Rumuoparani sp.

main breeding site of this species extends from Choba and only in September and November

Elele Aliminito Oduoha. Sympetrum navasi was 1990 from Rumuji (Tab. II) indicating that the

the from Oduoha collected throughout year to main breeding site of this species extends from Nolul. 4. No. I. June I. IW3 odonalol.. Vol. pp. 1-20. 15

Oduoha Choba Thus. Oduoha univollinc the that all lo (Fig. I). appears are contrary to hypothesis to be the transition site between Elele Alimini - are multivoltine in the tropics.

Rumuji and Isiodu - Choba sample sites. In spite ofwhat is already known and the infor-

Some collected this species during study, such mation gained from this study, our knowledge of

as Chalcostephia flavifrons, Sympetrum navasi, Afrolropical dragonflies is still very deficient es-

Trithemis stictica, and Urothemis edwardsi, breed pecially in the area of biology. Afrolropical

throughout the year because their larvae were dragonflylarvae are very poorly known and there

collected the of this has association throughout period study. been very little between larvae

such Macromia and Others, as sp. Cyanothemis and adults of the same species. Without studying

breed of in the simpsoni only once a year; their larvae this aspect, our knowledge dragonflies

collected in November 1989 and November in other of the world, will still were area, or any part

be all the adults collected 1990 (Tab. II). GAMBLES (I960) stated that in deficient even if are

Nigeria, there is nothing to prevent dragonflies and identified.

from breeding continuously throughout the year,

provided that water is available. Also. HYNES Acknowledgements - Special thanks to FA-

(1970) stated that in view ofthe unvarying tempe- MOUS OJARIKRE, PASIYA OTUFU and EM-

and conditions in the it MANUEL DEMA for technical assistance and rature light tropics may

be that reproduction and growth are continuous, to Drs S.J. BROOKS (British Museum, Natural

with all stages present at all times. The observa- History) and R.W. GARRISON (Asuza, Califor-

tions in this study indicate that these hypotheses nia. USA) for identification of the specimens.

while breed are partially true; some species

the others breed References - AMERICAN PUBLIC HEALTH throughout year, only once a

ORGANISATION Standard year. [AFHA], 1985, me-

Some dragonflies collected during this study thods for the examination ofwater and wastewa-

have been reported elsewhere. For instance, ter. 16th ed„ Washington DC; - DUMONT. H.J..

Chalcostephia flavifrons has been reported from 1977, Revue Zoo!, afr. 91: 573-586; - 1978.

Gabon and Cameroons (PINHEY, 1962). DU- ibid. 92: 303-315; - GAMBLES, R.M., 1960.

MONT (1977, 1978) reported Urothemis ed- .//. W. Afr. Sci. Ass. 6: 18-26; — 1966, Entomolo-

wardsi from Nigerand Mali. Hadrothemis infesta gist 99: 161-173; - 1970, ibid. 103: 53-61; -

has been reported from Cameroons (PINHEY, 1971 .ibid. 104: 177-189; - 1972, Odonalolo-

1962). gica I: 245-247; - HYNES, H.B.N.. 1970. The

Our knowledgeofAfrolropical dragonflieshas ecology of running waters. Liverpool. Univ.

been enhanced by the information gained from Press, Liverpool; - LINDLEY. R.P., \910. Ento-

this The of the distribution of the - study. scope mologist 103:77-83; PARR, M.J., 1974, Odo-

species which have been reported elsewhere is natolpgica 3: 187-189; - PARR, M.J. & M.

widened by the knowledge that such species also PARR, 1972, ibid. I: 257-261; - 1974. ibid. 3:

in this ofthe world. - Em. occur part Equally interesting 21-47; PINHEY, E„ 1967a, man. Mag.

is the fact that larvae distribution along the river 96: 256-271; - 1961b, ibid. 97: 101-114; -

is significantly affected by Chloride and BOD. 1962,./. enl. Soc. sth. Afr. 25: 20-50; - 1971.

Thus, unlike aerial distribution of adults, larval ibid. 34: 215-230.

distribution can be greatly influenced by a series

ofchemical factors. This study also revealed that

multivoltine while some dragonflies are others Received November 2.1. 1992