Activity Rithms and habitat of Hemidactylus turcicus (Reptilia, Gekkonidae) in Évora, Portugal

Mateus, O., & Jacinto J. J. (1998).  Activity Rithms and habitat of Hemidactylus turcicus (Reptilia, Gekkonidae) in Évora, Portugal. Cuadernos ICIJA. 2, 37-43.


A survey of Hemidactylus turcicus (Reptilia, Gekkonidae) was carried out every 3 weeks from March to November of 1997, in nocturnal transects in the city of Évora, Portugal. In this country this species is strictly nocturnal with a mean daily activity peak at 2hOO A.M (UTC).A model that correlates Activity and Temperature of the air is given. H. turcicus prefers, as microhabitat, walls (78%) and doors (16%) of low used houses. The average height in which they were found is about 3 meters.

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There are 3 species of Gekkonidae in Portugal:
Tarentola bischoffi
Tarentola mauritanica
Hemidactylus turcicus
The species Tarentola bischoffi is endemic of the insular territory of Selvagens (Archipelago of Madeira). The other two exist in Portugal, mostly in the south half, existing pIaces where they live together(sympatry), like, for instances, in Montemor-o-
Novo and Sines (Alentejo) and Aldeia das Açoteias (AIgarve), etc., (personaI observations) and places where there exists allopatry probabIy due to a competitive exc1usion like in Évora

H. turcicus is distributed all over the mediterranean coast and
extends East to India and South up to the North of Kenya. It was
introduced in the american continent, existing in the USA, cuba
and Mexico (FRETEY, 1987). The Portuguese subspecies is H.
turcicus turcicus. The "Livro Vermelho de Vertebrados de
Portugal" (SNPRCN, 1 990) c1assifies this species as
Insufficiently Known while the "Lista Roja de Espana" (ICONA,
1986) c1assifies it as Not Threatened. T. mauritanica is
c1assified as Not Threatened in both countries (portugal and
Spain). These two species are found especially in urban
environrnent, however T. mauritanica is often associated with
low density forests.
H. turcicus is known by its' vocal behaviour (FRANKENBERG,
1982). In this species, the voice plays a very important role in
the establishment and delimitation of the territories.
In H. turcicus the timing of social activity seems to differ from
that of foraging. The distribution partem of vocal interactions
throughout the day corresponds to locomotion activity
(FRANKENBERG, 1978) but not to the field counts of active
geckos (KING, 1958; ROSE & BARBOUR, 1968). Most vocal
activity occurs during the afternoon, before foraging starts
The Gekkonidae are accepted as nocturnal reptiles
(FRANKENBERG, 1982). The Portuguese H. turcicus's activity
patterns are poorly known, although a few data are described for
some other countries: Frankenberg (1978) measured, in Israel, a
nocturnal locomotion activity in the Summer, diurnal-noctumal
in Auturnn and Winter and diurnal activity in Spring using
laboratory data. In France has a strict1ynocturnal range activity:
leaves the perch site with the begining of the night and perched
again at morning totalling about 9 hours of activity
(DELAUGERRE, 1984 cit. in FRETEY, 1987). ln Texas, USA,
the circadian activity starts at night increasing till midnight,
from which decrease abruptly(SELCER, 1986).

The study area consists in a about 800 meters transect of
several streets with low human use of Évora's world Heritage
site (South PortugaD. The transect, chosen by its high frequency 

ofH. turcicus (MATEUS, 1996), was carried out every 3 weeks
(sampling) to determine the activity rhythms along the study
period (from March to November, 1997). In each sampling, the
transect was carried out every 2 hours (shifts), from 18 hours to
06 hours (U T.C.- Universal Time Coordinated) of the next day
to observe the circadian field activity. The transect was always
accomplished by the authors simultaneously, and each shift took
about 30 minutes to finish.
There were not made samplings before March, because
preliminary data (MATEUS, 1996 & pers. observ.) showed total
absence ofH.turcicuS's activity in Winter, and according to Zari
(1996), in Saudi Arabia, the H. turcicus is active since March to
November but only in the warmest night in Winter. It was also
considered that there was not any activity during day light hours
(these do not inc1ude twilight) that was confirmed by our
samplings. For each observed individual it was recorded the age
rank, comparing the approximated snout-vent-length (SVL) with
Se1cer's criteria ( 1986), where individuals > 44 millimeters are
considered adults. It was also recorded microhabitat,
approximated height in which each individual was observed, air
temperature and time of each observation.
Habitat and Microhabitat
Hemidactylus turcicus was found mostly in low human use
streets and in uninhabited or less used houses. The microhabitat
registered were walls (78%), doors or nearby them (16%),
street-lamps or nearby them (5%) and others ( 1%) (see Graphic
1). The average height in which we found H. turcicus was 3.9
(s.d.=1.9; n=393). As cryptic species, the perch sites and shelters
are, usually, in small holes and slits of the roofs, doors, walls,
windows, etc. It was usually also found hidden between the wall
and electric cords or tubing. Sometimes prefer high1y lighted
places where there is more prey.

Circadian Activity.
Gf'..lphil· 1: Microhabitut cof Hcntidactylus
fure/eu" it1 E,.(w<I.
There were observed individuals from 20hOOto 6hOOUTC (see
Graphic 2). The mean activity peak is at 2hOOUTC, although
we registered a few peak at 22hOOand OhOOUTC. This data
differs from the circadian activity described by Selcer ( 1986)
and Frankenberg (1978) cited in the Introduction; the
geographical position ofthe each country study (USA and Israel,
respectively) may explain the diference. In the second study we
can also point out some differences due to the nature of that
study (Frankenberg measured the real locomotion activity in a
laboratory). However, the activity referred by Zari (1996) and
Delaugerre (1984, cit. in FRETEY, 1987) supports our data. 

Circannual Activity
The results revealed themselves quite oscillating along the study
period due, essentially to abiotic factors variations (air
temperature and moister). The activity observed along the
transect during the 2hOOUTC shift has a relation with the
temperature (measured in "C) that can be translated by the
Activity=4.051 + 8.342xlOE-19 TempE15.
With a Correlation Coefficient de 0.901 and an Adjusted R2 of
0.791. However, the activity is not strictly connected with the
temperature, because the time of the day and or the hour of the
shift seems to be very relevant. There were not observed
individuals by day or twilight even with warm temperatures.
This linear regression permits prediction, with an accuracy of
90%, the number of individuals that will be seen at 2hOOUTC
in the transect through air temperature. To obtain this equation
we use the 2hOOUTC shift because that shift average is the one
with greater average activity.

Acknowledgments: We wish to thank Andreia Salvador,
Catarina Azinheira, João Tiago Tavares, Mark Carter, Pedro
Guilherme, Sérgio Pereira and Susana Celestino.
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