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Effect of Temperature on the Development and Survival of the Argentine Ant, Linepithema humile

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The influence of temperature on the developmental times and survival of insects can largely determine their distribution. For invasive species, like the Argentine ant, Linepithema humile Mayr (Hymenoptera: Formicidae), these data are essential for predicting their potential range based on mechanistic models. In the case of this species, such data are too scarce and incomplete to make accurate predictions based on its physiological needs. This research provides comprehensive new data about brood survival and developmental times at a wide range of temperatures under laboratory conditions. Temperature affected both the complete brood development from egg to adult worker and each of the immature stages separately. The higher the temperature, the shorter the development times. Brood survival from egg to adult was low, with the maximum survival rate being only 16% at 26º C. Temperature also affected survival of each of the immature stages differently: eggs were negatively affected by high temperatures, while larvae were negatively affected by low temperatures, and the survival of pupae was apparently independent of environmental temperature. At 32º C no eggs survived, while at 18º C less than 2% of the eggs hatched into larva. The data from the present study are essential for developing prediction models about the distribution range of this tramp species based on its physiological needs in relation to temperature.
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Journal of Insect Science: Vol. 10 | Article 97 Abril et al.
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Effect of temperature on the development and survival of
the Argentine ant, Linepithema humile
Sílvia Abrila, Jordi Oliveras, and Crisanto Gómezb
Department of Environmental Sciences, University of Girona, Montilivi Campus s/n, 17071 Girona, Spain
Abstract
The influence of temperature on the developmental times and survival of insects can largely
determine their distribution. For invasive species, like the Argentine ant, Linepithema humile
Mayr (Hymenoptera: Formicidae), these data are essential for predicting their potential range
based on mechanistic models. In the case of this species, such data are too scarce and incomplete
to make accurate predictions based on its physiological needs. This research provides
comprehensive new data about brood survival and developmental times at a wide range of
temperatures under laboratory conditions. Temperature affected both the complete brood
development from egg to adult worker and each of the immature stages separately. The higher the
temperature, the shorter the development times. Brood survival from egg to adult was low, with
the maximum survival rate being only 16% at 26º C. Temperature also affected survival of each
of the immature stages differently: eggs were negatively affected by high temperatures, while
larvae were negatively affected by low temperatures, and the survival of pupae was apparently
independent of environmental temperature. At 32º C no eggs survived, while at 18º C less than
2% of the eggs hatched into larva. The data from the present study are essential for developing
prediction models about the distribution range of this tramp species based on its physiological
needs in relation to temperature.
Keywords: brood developmental times, brood survivorship rate, Formicidae, Hymenoptera, invasive species
Correspondence: asilvia.abril@udg.edu, bcrisanto.gomez@udg.edu
Associate Editor: Robert Jeanne was editor of this paper.
Received: 30 May 2008, Accepted: 17 October 2008
Copyright : This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits
unrestricted use, provided that the paper is properly attributed.
ISSN: 1536-2442 | Vol. 10, Number 97
Cite this paper as:
Abril S, Oliveras J, Gómez C. 2010. Effect of temperature on the development and survival of the Argentine ant,
Linepithema humile. Journal of Insect Science 10:97 available online: insectscience.org/10.97
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Introduction
The Argentine ant, Linepithema humile Mayr
(Hymenoptera: Formicidae), is well known as
an invasive ant species (McGlynn 1999).
Native to South America (Tsutsui et al. 2001)
it has now been introduced into various parts
of the world as a result of human commercial
activities (Hölldobler and Wilson 1990;
Suarez et al. 2001). Its distribution includes
areas with Mediterranean-type climates
(Passera 1994; Vega and Rust 2001). Its rapid
expansion in invaded zones has been
facilitated by habitat disturbance (Suarez et al.
1998), but there is increasing evidence of its
ability to occupy non-altered habitats (Cole et
al. 1992; Holway 1998). In such areas its
capacity to negatively affect native ant faunas
(Camell et al. 1996; Human and Gordon 1997;
Suarez et al. 1998; Holway 1999; Gómez and
Oliveras 2003; Sanders et al. 2003) through
intense interference and exploitative
competition (Holway 1999) has been widely
reported. It is also recognized that climatic
factors are the key elements that determine its
distribution in invaded areas (Roura-Pascual
et al. 2004), especially environmental
temperature and water availability (Human et
al. 1998; Holway et al. 2002; Menke and
Holway 2006). Temperature has a strong
influence on some reproductive traits of the
species: for example, the queens’ oviposition
rate (Newell 1909; Benois 1973; Abril et al.
2008). L. humile brood development rate also
seems to be strongly affected by
environmental temperature (Newell and
Barber 1913; Benois 1973), although data
concerning this aspect of its biological cycle
are very scarce and incomplete. Such data are
essential for predicting, for example, the
timing of plague outbreaks or the
geographical limits of an insect’s distribution
(Hartley and Lester 2003). To date, there is
little knowledge about how the Argentine
ant’s biological needs influence its
distribution range, since most of the prediction
models that have been made are only based on
its climatic requirements (Roura-Pascual et al.
2004). Up to now, only few prediction models
based on the physiological needs of L. humile
have been made (Hartley and Lester 2003;
Krushelnycky et al. 2005), probably due to the
poor data available about the influence of
abiotic factors on the species’ biological
cycle.
The relationship between temperature and
brood development rates is a useful
component in models predicting the areas
most suitable for the species to become
established in, based on its physiological
needs, and as a tool for predicting future
changes in its present distribution range as a
result of global climate change. However,
such models need a considerable amount of
data in constant temperature environments to
be accurately calibrated (Blank et al. 2000),
and the currently available data on the
Argentine ant’s brood development rates have
a lack of replicates for each measured
temperature, and daily averages instead of
fixed temperatures were used to obtain brood
developmental times (Newell and Barber
1913; Benois 1973).
The purpose of this study is to obtain new data
about the Argentine ant’s brood development
times in relation to environmental
temperature, not only to improve current
knowledge of this species’ biology, but also to
provide valuable information which will allow
the creation of accurate prediction models
based on its physiological needs.
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Materials and Methods
Ant collection and laboratory colonies
L. humile used in the study were collected in
March 2006 from an invaded natural area
situated on the southern edge of the Gavarres
Massif near the village of Castell d’Aro (NE
Iberian Peninsula) (41º 49’ N, 3º 00’ E).
L. humile (14 queens from 14 nests and
numerous workers) were collected to create
14 artificial monogynous nests each
containing one queen and approximately 300
workers. The nests were incubated at 28º C,
which is the optimal temperature for queen
oviposition in L. humile (Abril et al. 2008).
The nests were a variant of those described by
Passera et al. (1988), made up of a regular
plastic box (180 mm x 115 mm and 35 mm
high). The box was fitted with a layer of dry
plaster of Paris and was connected laterally to
a smaller plastic box (75 mm x 50 mm and 25
mm high) by a cotton wool wick permanently
in contact with a piece of cotton soaked in
water. To prevent escape, the inner sides of
the main plastic box were coated with liquid
PTFE (Fluon). The ants were fed daily with a
variant of the artificial diet described by
Keller et al. (1989). Hashed beef meat was
replaced with royal jelly, and the sugar was
replaced with honey. The food was not coated
with paraffin, but was placed directly on the
nest floor. We knew this diet to be very
suitable for rearing L. humile colonies
because it allowed a high fecundity in queens
(Abril et al. 2008) and the production of
healthy workers and sexuals, both males and
queens. The incubation time of these colonies
was two weeks. After this period each queen
was allowed to lay eggs to obtain the eggs for
the study following the same procedure as in
Abril et al. (2008).
Total brood developmental times and
survival rates of the worker caste
To study the total immature development
period of the worker caste from egg to adult, a
total of 100 eggs from the oviposition tests
mentioned above were placed in artificial
queenless colonies containing approximately
600 workers without brood. In the case of 18º
C and 32º C, to obtain reliable data in those
extreme conditions, a total of 400 eggs was
tested instead of the usual 100.
The artificial colonies were acclimated at
ambient temperature in the lab (24-25º C) for
two hours, and then they were kept in
environmental chambers at one of seven
experimental temperatures (º C ± SD): 18 ±
0.1, 21 ± 0.1, 24 ± 0.1, 26 ± 0.1, 28 ± 0.1, 30
± 0.1, and 32 ± 0.1. As differences in
acclimation could generate differences in the
results obtained from each temperature
analysed (Jumbam et al. 2008), the same
acclimation conditions were used for all
treatments.
Observations were carried out daily, and the
exact worker development times at each of the
seven experimental temperatures were noted.
the brood survival rate at each temperature
from egg to adult form (including the sexuals)
was calculated by means of the data obtained.
Development times and survival rate of
each immature stage
An ant’s development from egg to adult form
includes three different stages: egg stage,
larval stage, and pupal stage. the effect of
temperature on development and survival in
each of these three stages was studied also.
Due to the small size of the eggs and the
difficulty of observing them in the artificial
nests (the workers tended to carry them
quickly through the nest when observing them
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under the binocular microscope), additional
eggs were incubated in test tube nests instead
of in artificial queenless colonies at each of
the seven experimental temperatures. The
number of eggs tested varied depending on the
queen’s egg-laying at each temperature and
ranged from 105 to 354. The eggs’ incubation
in the test tube nests was performed without
the presence of any workers because previous
observations had shown us that there were no
differences between the viability of eggs in
the care of workers and the viability of eggs
without such care, and the observation and
individualization of the eggs were easier
without workers (when observed under a
binocular microscope, they tended to carry the
eggs in big masses). The eggs were observed
daily from the first day of egg-laying to the
appearance of the larva. In this way, more
accurate data was obtained by noting the exact
number of days from egg to larvae for each
egg that hatched. the survival rate of the eggs
at each of the seven experimental
temperatures was also calculated.
The small size of new-born larvae made it
difficult to obtain reliable data about
development times in this stage. Therefore,
the times were estimated by taking the
difference between the total brood
development time and the sum of the egg
stage and the pupal stage development times.
The survival rate of this stage was also
estimated from these data.
The duration of the pupal stage at each of the
seven experimental temperatures was
measured taking the data from the daily
observations of the artificial queenless
colonies set up to obtain the total brood
development times of the species. Survival
rates were also calculated in this stage at each
of the experimental temperatures.
Results
Total brood development times and
survival rates of the worker caste
Temperature substantially affects brood
development in L. humile. The higher the
temperature, the shorter the brood
development times (Figure 1). As egg
Figure 1. Total developmental times of the Argentine ant, Linepithema humile, from egg to adult worker. High quality figures
are available online.
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development stopped at 32º C, it can be
assumed that this was the upper limiting
temperature for total brood development from
egg to adult form. In consequence, the larval
and pupal development times at this
temperature were not analyzed. At 18º C, the
survival of the eggs was almost zero: only
1.7% of incubated eggs achieved emergence.
For this reason, it was assumed that total
development from egg to adult worker at 18º
C would be negligible, and therefore, the
larval and pupal development times were not
analyzed at this temperature.
The brood survival rate, expressed in
percentage terms, is at its maximum at 26º C
and decreases with higher and lower
temperatures (Figure 2).
Table 1 summarizes the temperature ranges
for brood and worker survival, development,
queen oviposition and foraging activity in L.
humile. We can see that the optimal
temperature for the brood survival rate is close
to that reported for the queen oviposition, and
that these are included within the optimal
range of foraging activity, which ranges from
5-15º C to 30-34º C. Above and below this
range are the species’ lower and upper
thresholds for oviposition and foraging
activity and the upper and lower lethal limits
for survival (Table 1).
Developmental times and survival rate of
each immature stage
The duration of the egg stage declined from
58 days at 18º C to less than 15 days at 30º C
(Figure 3). Eggs at 32º C in the test tube nests
(a total of 105) failed to develop because all
died in the first two weeks of incubation. At
18º C, virtually none of the incubated eggs in
the test tube nests survived: only three of 173
eggs emerged into larva, and the rest died.
The eggs placed in the artificial queenless
colonies at 32º C (a total of 400) also died in
the first two weeks of testing, undoubtedly
killed by the extreme temperatures. The
incubation range of days decreased as
temperature increased (Figure 3). The survival
rate of the eggs of this species was negatively
Figure 2. Effect of temperature on brood survival from egg to adult form in the Argentine ant, Linepithema humile.High
quality figures are available online.
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affected by high temperatures since only
about 13% emerged into larva at 30º C, in
comparison with about 52% which emerged
into larva at 21º C. Below 21º C the eggs’
survival rate was again negatively affected by
temperature, since only 1.7% of the eggs
achieved the larval stage at 18º C (Figure 4).
The estimated duration of the larval stage
decreased as temperature increased (Figure 5).
The range of days to pupal emergence
decreased with increasing temperatures. A
marked variation in the duration of this stage
between samples incubated at the same
experimental temperatures (Figure 5) also was
observed. The survival rate of this stage
seemed to be negatively affected by low
temperatures, since only about 19% of the
larvae pupated at 21º C, compared with the
94% estimated at 30º C (Figure 4).
Within the range tested, the duration of the
pupal stage declined from about 25 days at 21º
C to about 8 days at 30º C (Figure 6). The
range of days of the emergence to adult
worker varied little, from one to three days of
difference (Figure 6). In contrast to eggs and
larvae, the survival of pupae was always
100%, apparently independent of temperature
(Figure 4).
Discussion
The results show that, as was expected, under
the range studied (18-32ºC), temperature
affected the development times of both the
Table 1. Temperature ranges for brood survival and development reported in the present work with those reported in the
bibliography for queen oviposition, worker survival and activity.
Temperature (ºC) Experimental / Field
conditions
Study
Brood survival
optimal temperature from
egg to adult development 26ºC Experimental conditions
This study
lower lethal temperature for
egg development ~18ºC Experimental conditions
This study
upper lethal temperature for
egg development 32ºC Experimental conditions
This study
Oviposition
optimal temperature 28ºC Experimental conditions
Abril et al. 2008
lower temperature
threshold 17-18ºC Experimental conditions
Newell and Barber 1913
lower temperature
threshold 10-18ºC Experimental conditions
Abril et al. 2008
upper temperature
threshold 32-34ºC Experimental conditions
Abril et al. 2008
Worker survival
critical thermal minimum 0-0.8ºC Experimental conditions
Jumbam et al. 2008
critical thermal maximum 38-40ºC Experimental conditions
Jumbam et al. 2008
lower lethal temperature - 4 to 10.5ºC Experimental conditions
Jumbam et al. 2008
upper lethal temperature 46ºC Experimental conditions
Holway et al. 2002
upper lethal temperature 45-47ºC Experimental conditions
Walters and Mackay 2004
upper lethal temperature 37-44ºC Experimental conditions
Jumbam et al. 2008
Foraging activity
optimal temperature 15-30ºC Field conditions (California)
Markin 1970
optimal temperature ~34ºC Field conditions (California)
Holway et al. 2002
lower temperature
threshold 5-10ºC Field conditions (California)
Markin 1970c; Human et al.
1998
lower temperature
threshold 5-10ºC Field conditions
(South Africa)
Witt and Giliomee 1999
lower temperature
threshold 5ºC Field conditions
(Catalonia, Spain)
Abril et al. 2007
upper temperature
threshold
40-44ºC Field conditions
(South Africa)
Witt and Giliomee 1999
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complete brood development from egg to
adult worker and each of the immature stages
in the same manner: the higher the
temperature, the shorter the developmental
times. This relation was reported by Newell
and Barber (1913) almost one hundred years
ago. However, our results are generally
consistent with those of Newell and Barber
(1913) although our data show somewhat
longer developmental times than they
Figure 3. Duration of the egg stage of the Argentine ant, Linepithema humile, at different temperatures. High quality figures
are available online.
Figure 4. Effect of temperature on the survival of each of the immature stages of the Argentine ant, Linepithema humile. High
quality figures are available online.
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reported, presumably due to their low number
of replicates or differences in experimental
conditions.
The effect of environmental temperature on L.
humile brood development times that was
observed in this study has also been observed
for other ant species (Porter 1988; Arcila et al.
2002), and in comparison with the results
obtained for L. humile, the developmental
times for some ants like Solenopsis invicta
(Porter 1988), Paratrechina fulva (Arcila et
Figure 5. Duration of the larval stage of the Argentine ant, Linepithema humile, at different temperatures. High quality figures
are available online.
Figure 6. Duration of the pupal stage of the Argentine ant, Linepithema humile, at different temperatures. High quality figures
are available online.
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al. 2002) or Anoplolepis longipes (Rao and
Veeresh 1991) are in general shorter, while
Prenolepis imparis (Tschinkel 1987) has
longer developmental times than L. humile at
similar conditions of temperature and
humidity (27º C, 80% RH).
The upper limit of egg development was 32º
C; at this temperature egg survival was zero.
The lower temperature limit seemed to be
around 18º C; at this temperature the survival
of the eggs was practically zero: only three
eggs out of 173 emerged into larva. Further
research is necessary to know about survival
rates and development times for the larval and
pupal stages at temperatures above 32ºC and
lower than 18ºC. Because these seem to be the
temperatures at which egg development stops,
the temperature limit for the survival and
development of these two brood stages could
be more extreme than those studied in the
present work.
In the case of larval developmental times,
there is a marked variation between the
development times of samples subjected to the
same temperature treatment. This could be
due to the fact that this form is the only one
that is fed by workers (Markin 1970a). This
being the case, it would seem that larval
developmental times are not only affected by
environmental temperature, but also by the
food they ingest. This would explain why
such a marked difference is only observed in
this phase.
Brood survival rate also varies as a function of
environmental temperature within the range
tested. While eggs were negatively affected as
the temperature rose, larvae were negatively
affected by low temperatures. This can be
explained in the light of the biological cycle
of this species in its natural environment. In
spring and autumn when the environmental
temperature is cool, L. humile queens are at
their maximum egg-laying period and the
maximum egg densities are in the nest at this
time, while maximum larvae densities appear
at the end of spring when the temperatures are
warmer (Markin 1970b; Benois 1973).
Therefore, it seems that the L. humile
biological life cycle, as far as brood
development is concerned, is adapted to the
physiological temperature needs of each
immature form almost during their maximal
densities in natural nests. It would allow the
maximal survival of the different brood
stages, and in consequence, the maximal
reproductive success of the colony.
The high survival rate observed in pupae at all
the experimental temperatures tested in this
study indicates that this phase is the most
resistant to temperature variation. This is in
accordance with the observations made by
Porter (1988), who observed high levels of
survival, not related to temperature, in pupae
of the ant species Solenopsis invicta.
The total brood survival from egg to adult
observed in this study was quite low. Only 16
out of 100 eggs reached adult form under the
optimal survival temperature of 26º C. In that
sense, the percentages of brood survival
observed in the present study are in agreement
with the ones observed under experimental
conditions and similar rearing conditions of
temperature and humidity (27º C and 80%,
respectively) by Arcila et al. (2002) for the ant
species Paratrechina fulva. She found a
survival of 30% in eggs and of approximately
50% in larvae, the same percentages obtained
in that study at 28º C for L. humile. This fact
provides confidence in the results obtained.
Moreover, studies carried out 50 years ago in
Portugal (Silva Dias 1955) on the relationship
between brood development times of L.
humile and environmental temperature,
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revealed again this low brood survival under
experimental conditions. They tried to obtain
complementary data to that obtained by
Newell & Barber (1913) concerning
development from larvae to pupae and from
pupae to adult worker. But in the end they
were only able to obtain three more pieces of
data at different ambient temperatures (larvae
to pupae: temperature 19º C; days of
development = 30-31. Pupae to adult worker:
mean ambient temperature = 19º C; days of
development = 24-26, 25º C; 12-16 days and
23º C; 16-17 days). This was probably due to
the low brood survival rate of this species, at
least under experimental conditions, that was
observed in the present study.
We believe that brood survival would
probably be higher in natural nests due to the
thermal gradient present in the nest and the
fact that environmental temperature is not
constant, but changes throughout the day. The
overall likelihood is that this would be used
by the workers to incubate the different brood
stages at their optimal survival temperature
and, in short, assure the maximum
reproductive success of the colony. Even
though further research is necessary to
confirm this, the data given in the present
study are very valuable, not only because
there are no other studies which offer
comprehensive, accurate data about the brood
developmental times of L. humile at a wide
range of fixed temperatures, but also because
these data are essential for developing
prediction models about the distribution range
of this tramp species based on its
physiological needs in relation to temperature.
Acknowledgements
We are grateful to Dr. L. Passera for his useful
advice about artificial nests and two
anonymous referees for their comments on the
manuscript. This study was financed by the
Spanish Ministry of Education and Science
(CGL2004-05240-C02-02/BOS and MEC/
FEDER2007-64080-C02-02/BOS). S. Abril
was supported by a grant financed by the
University of Girona.
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... ants, herbivores) population densities. In particular, insect abundance usually increases towards the rainy season (and with higher temperatures) because these climatic conditions enhance consumption rates and decrease the time of development (Abril, Oliveras, & Gómez, 2010;Ratte, 1985). Climate might also indirectly (via plant phenology) influence ant-plant mutualistic interaction (Heil, 2015). ...
... Therefore, greater activity of these protective structures (Calixto et al., 2015) is Seasonal variation in the abundance of ants and herbivores were also related to seasonal climatic conditions of the Brazilian Cerrado (Vilela et al., 2014. The seasonality of insect abundance would reflect the temporal patterns of rainfall in regions with a marked seasonality, where the number of insects decreases during the dry season and increases during the rainy season (Abril et al., 2010;Coley & Barone, 1996;Ratte, 1985). However, these relationships can be also strongly influenced by plant phenology and sequential flowering in the Brazilian Cerrado (Vilela et al., 2014). ...
... Camponotus crassus, in a cerrado sensu stricto vegetation was greater during the months with greater rainfall. Similarly, we also found that temperature had positive direct effects on ant abundance, probably trough increases in consumption rates and body size, and decreases in developmental time of ants (Abril et al., 2010;Ratte, 1985). For instance, Abril et al. (2010) showed that temperature affected the complete brood development of the Argentinian ant Linepithema humile, in which the higher the temperature, the shorter the development times. ...
Article
Interactions between ants and plants bearing extrafloral nectaries (EFNs) are among the most common mutualisms in Neotropical regions. Plants secrete extrafloral nectar, a carbohydrate‐rich food that attracts ants, which in return protect plants against herbivores. This ant‐plant mutualism is subjected to temporal variation, in which abiotic factors can drive the establishment and frequency of such mutualistic interaction. However, studies investigating how abiotic factors (e.g., climate) directly and indirectly influence ant‐plant‐herbivore interactions are incipient. In this study, we investigated direct and indirect (via plant phenology) effects of temperature and rainfall on ant‐plant‐herbivore interactions. To address these goals, each month we estimated six plant phenophases (newly flushed leaves, fully‐expanded leaves, deciduousness, floral buds, flowers, and fruits), the activity of EFNs and abundance of ants and herbivores in 18 EFN‐bearing plant species growing in a markedly seasonal region (the Brazilian Cerrado) during a complete growing season. Our results showed that (i) there were marked seasonal patterns in all plant phenophases, EFN activity, and the abundance of ants and herbivores; (ii) the peak of EFN activity and ant and herbivore abundance simultaneously occurred at the beginning of the rainy season, when new leaves flushed; and (iii) rainfall directly and indirectly (via changes in the production of new leaves) influenced EFN activity and this in turn provoked changes in ant abundance (but not on herbivores). Synthesis: Overall, our results build toward a better understanding of how climate drives seasonal patterns in ant‐plant‐herbivore interactions, explicitly considering plant phenology over time.
... As evidenced herein and in numerous other subsequently listed works, air temperature plays a critical and influential role in various aspects of invertebrate life history. Elevated air surface temperatures from climate change could affect life history traits such as fecundity and reproductive capacity (Chen et al., 2010;Grazer & Martin, 2012); alter surface activity and copulatory behavior (Jiao et al., 2009;Katsuki & Miyatake, 2009;Pulz, 1987); affect organismal development (Abril et al., 2010;Atkinson, 1994;Kiss & Samu, 2002); reduce survival of individuals at varying life stages (Abril et al., 2010;Almquist, 1970;Davis, 1989); and shift phenological relationships between producers and consumers (Menzel et al., 2006). Within the study area, Gonzalez et al. (2018) projected that F I G U R E 5 Predicted abundance on sample collection dates of (a) adult spiders (Araneae), (b) ants (Hymenoptera: Formicidae), (c) harvestmen (Opiliones), and (d) crickets (Orthoptera: Gryllidae and Rhaphidophoridae) within observed temperature range. ...
... As evidenced herein and in numerous other subsequently listed works, air temperature plays a critical and influential role in various aspects of invertebrate life history. Elevated air surface temperatures from climate change could affect life history traits such as fecundity and reproductive capacity (Chen et al., 2010;Grazer & Martin, 2012); alter surface activity and copulatory behavior (Jiao et al., 2009;Katsuki & Miyatake, 2009;Pulz, 1987); affect organismal development (Abril et al., 2010;Atkinson, 1994;Kiss & Samu, 2002); reduce survival of individuals at varying life stages (Abril et al., 2010;Almquist, 1970;Davis, 1989); and shift phenological relationships between producers and consumers (Menzel et al., 2006). Within the study area, Gonzalez et al. (2018) projected that F I G U R E 5 Predicted abundance on sample collection dates of (a) adult spiders (Araneae), (b) ants (Hymenoptera: Formicidae), (c) harvestmen (Opiliones), and (d) crickets (Orthoptera: Gryllidae and Rhaphidophoridae) within observed temperature range. ...
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• The central Appalachian shale barrens, a globally unique habitat type restricted to the eastern United States, presents an insular and physiologically stressful environment with sparse vegetation and extreme ground surface and air temperatures. Despite the high levels of plant species endemism within these systems, information on invertebrate communities and habitat preferences is extremely limited. • Through this study, we aimed to better understand a shale barren arthropod community, microhabitat selection, and the influence of habitat characteristics and climatic factors. We employed pitfall traps to sample epigeic arthropods during the 2016 growing season in a shale barren habitat. • Arthropod community composition was driven by overstory trees, mediated through accumulated leaf litter and availability of shaded microhabitats. Ambient air temperature also influenced the surface activity of various taxa with spiders decreasing at higher temperatures and ants, crickets, flies, and harvestmen all increasing in relative abundance. • Habitat integrity of the central Appalachian shale barrens is threatened by forest succession and mesophication, encroaching invasive plant species, and rising ambient air temperatures, all of which can alter the extent of overstory vegetation and availability of shaded microhabitats. These biotic and physical pressures will subsequently affect epigeic arthropod community composition, depending on adaptive capacity of individual taxa. • To the authors’ knowledge, these findings constitute only the second published work on arthropod communities and the first to focus on epigeic taxa in this globally rare habitat type. Continued conservation of these unique, insular habitats and their adapted inhabitants requires a multifaceted approach that considers current and future conditions.
... Such changes in the soil may also affect the development of larger organisms. Because ant development varies with environmental conditions (89), the delayed egg development may be explained by manure-induced changes in oxygen-levels. As insect eggs depend on oxygen for their development, they have diffusion holes in the shell (90,91). ...
... Environmental temperature in turn affects their metabolism (Hazel and Prosser, 1974). In particular, it seems widespread that developmental speed increases with rearing temperature in poikilothermic species (Abril et al., 2010;Asano and Cassill, 2012;Hrs-Brenko et al., 1977;Ikemoto, 2005;Manoj Nair and Appukuttan, 2003;Nishizaki et al., 2015;Pechenik et al., 1990;Porter, 1988;Sharpe and DeMichele, 1977;Vélez and Epifanio, 1981), including various Drosophila species (David and Clavel, 1966;James and Partridge, 1995;Kuntz and Eisen, 2014;Powsner, 1935). This phenomenon is proposed to be due to thermodynamics of enzymes responsible for biochemical reactions underlying developmental processes (Crapse et al., 2021;Ikemoto, 2005;Schoolfield et al., 1981;Sharpe and DeMichele, 1977). ...
Article
Rearing temperature is correlated with the timing and speed of development in a wide range of poikiloterm animals that do not regulate their body temperature. However, exceptions exist, especially in species that live in environments with high temperature extremes or oscillations. Drosophila pachea is endemic to the Sonoran desert in Mexico, in which temperatures and temperature variations are extreme. We wondered if the developmental timing in D. pachea may be sensitive to differing rearing temperatures or if it remains constant. We determined the overall timing of the Drosophila pachea life-cycle at different temperatures. The duration of pupal development was similar at 25 °C, 29 °C and 32 °C, although the relative progress differed at particular stages. Thus, D. pachea may have evolved mechanisms to buffer temperature effects on developmental speed, potentially to ensure proper development and individual's fitness in desert climate conditions.
... While foragers easily avoid extreme temperatures by changing foraging times or choosing to forage on cooler substrates (Spicer et al. 2017;Stark et al. 2017), queens, brood, and nurses inside the cavity nest are less likely to escape thermal extremes. Exposure to thermal extremes, or frequent temperature variation, can be detrimental to ant colonies, because proper brood development requires optimal temperature (Abril et al. 2010;Oms et al. 2017). Since twig-nesting ants cannot rapidly alter their nest properties, they must either withstand thermal stress or abscond (i.e., evacuate the nest). ...
Article
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Tropical forests experience a relatively stable climate, but are not thermally uniform. The tropical forest canopy is hotter and thermally more variable than the understory. Heat stress in the canopy is expected to increase with global warming, potentially threatening its inhabitants. Here, we assess the impact of heating on the most abundant tropical canopy arthropods—ants. While foragers can escape hot branches, brood and workers inside twig nests might be unable to avoid heat stress. We examined nest choice and absconding behavior—nest evacuation in response to heat stress—of four common twig-nesting ant genera. We found that genera nesting almost exclusively in the canopy occupy smaller cavities compared to Camponotus and Crematogaster that nest across all forest strata. Crematogaster ants absconded at the lowest temperatures in heating experiments with both natural and artificial nests. Cephalotes workers were overall less likely to abscond from their nests. This is the first test of behavioral thermoregulation in tropical forest canopy ants, and it highlights different strategies and sensitivities to heat stress. Behavioral avoidance is the first line of defense against heat stress and will be crucial for small ectotherms facing increasing regional and local temperatures.
... Such changes in the soil may also affect the development of larger organisms. Because ant development varies with environmental conditions (89), the delayed egg development may be explained by manure-induced changes in oxygen-levels. As insect eggs depend on oxygen for their development, they have diffusion holes in the shell (90,91). ...
Article
Full-text available
Insects are integral to terrestrial life and provide essential ecosystem functions such as pollination and nutrient cycling. Due to massive declines in insect biomass, abundance, or species richness in recent years, the focus has turned to find their causes. Anthropogenic pollution is among the main drivers of insect declines. Research addressing the effects of pollutants concentrates on aquatic insects and pollinators, despite the apparent risk of contaminated soils. Pollutants accumulating in the soil might pose a significant threat because concentrations tend to be high and different pollutants are present simultaneously. Here, we exposed queens of the black garden ant Lasius niger at the colony founding stage to different concentrations and combinations of pollutants (brake dust, soot, microplastic particles and fibers, manure) to determine dose-dependent effects and interactions between stressors. As proxies for colony founding success, we measured queen survival, the development time of the different life stages, the brood weight, and the number of offspring. Over the course of the experiment queen mortality was very low and similar across treatments. Only high manure concentrations affected the colony founding success. Eggs from queens exposed to high manure concentrations took longer to hatch, which resulted in a delayed emergence of workers. Also, fewer pupae and workers were raised by those queens. Brake dust, soot and plastic particles did not visibly affect colony founding success, neither as single nor as multiple stressors. The application of manure, however, affected colony founding in L. niger negatively underlining the issue of excessive manure application to our environment. Even though anthropogenic soil pollutants seem to have little short-term effects on ant colony founding, studies will have to elucidate potential long-term effects as a colony grows.
... Environmental temperature in turn affects their metabolism (Hazel and Prosser, 1974). In particular, it seems widespread that developmental speed increases with rearing temperature in poikilothermic species (Abril et al., 2010;Asano and Cassill, 2012;Hrs-Brenko et al., 1977;Ikemoto, 2005;Manoj Nair and Appukuttan, 2003;Nishizaki et al., 2015;Pechenik et al., 1990;Porter, 1988;Sharpe and DeMichele, 1977;Vélez and Epifanio, 1981), including various Drosophila species (David and Clavel, 1966;James and Partridge, 1995;Kuntz and Eisen, 2014;Powsner, 1935). This phenomenon is proposed to be due to thermodynamics of enzymes responsible for biochemical reactions underlying developmental processes (Ikemoto, 2005;Schoolfield et al., 1981;Sharpe and DeMichele, 1977). ...
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Rearing temperature is correlated with the timing and speed of development in a wide range of poikiloterm animals that do not regulate their body temperature. However, exceptions exist, especially in species that live in environments with high temperature extremes or oscillations. Drosophila pachea is endemic to the Sonoran desert in Mexico, in which temperatures and temperature variations are extreme. We wondered if the developmental timing in D. pachea may be sensitive to differing rearing temperatures or if it remains constant. We determined the overall timing of the Drosophila pachea life-cycle at 25°C and 29°C. The duration of pupal development was similar at both temperatures although the relative progress differed at particular stages. Thus, D. pachea may have evolved mechanisms to buffer temperature influence on developmental speed, potentially to ensure proper development and individual’s fitness in desert climate conditions. Highlights In poikilotherms, developmental speed usually increases with rearing temperature Global pupal development of D. pachea is similar at two different rearing temperatures Discrete temperature dependent timing differences at specific pupal stages D. pachea development is longer compared to other Drosophila species Temperature-buffering mechanisms may have evolved to ensure a proper development
... Une température chaude stressante chez T. nylanderi réduit la taille des ouvrières produites et la variation de taille augmente chez Bombus impatiens (Kelemen & Dornhaus, 2018). Elle peut affecter la survie du couvain, une forte température est corrélée négativement à la survie des oeufs alors qu'à l'inverse les larves sont négativement affectées par une température basse (Abril, Oliveras, & Gómez, 2010). L'hibernation vécue par une larve influence fortement son devenir en reine (Brian, 1963(Brian, , 1973. ...
Thesis
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Chez les insectes sociaux, la diversité de taille des individus dans les colonies est supposée améliorer la division du travail et ainsi augmenter la fitness des colonies. Cela fait relativement consensus chez les espèces à forte diversité de taille continue ou bien avec la présence de plusieurs castes non reproductrices. En revanche, chez les espèces à diversité plus limitée, représentant la grande majorité des insectes sociaux, les résultats sont plus contrastés. Cette thèse s’est donc focalisée sur l’intérêt de la taille des ouvrières au sein des colonies de fourmis à diversité modérée. Nous avons dans un premier temps démontré que la taille moyenne et la diversité de taille des ouvrières ne sont pas forcément adaptatives chez notre espèce d’étude, Temnothorax nylanderi, à travers des manipulations expérimentales en milieu semi-naturel durant la période de croissance et durant l’hibernation. Face à ce manque d’intérêts de la taille des individus pour la colonie, nous avons investigué les potentiels intérêts pour les individus. En utilisant la fourmi Mystrium rogeri, nous avons manipulé la prise alimentaire des larves et ainsi étudié le développement des larves sans contraintes de la part des ouvrières. Ces données sur le développement larvaire suggèrent le développement de phénotypes plus grands en l’absence de coercion des larves par les ouvrières. Cela sous-entend à la fois que l’environnement social contrôle fortement la taille des individus produits, mais également qu’une perturbation de cet environnement social et/ou des comportements égoïstes des larves peuvent générer de la diversité de taille dans les colonies de fourmis. Dans un dernier chapitre, nous avons quantifié la contribution de cet environnement social dans la résistance à un perturbateur externe, en utilisant un élément trace. L’idée était de découpler la part sociale représentée par les ouvrières de la part intrinsèque des larves dans la résistance au cadmium en utilisant des colonies de la fourmi Temnothorax nylanderi provenant de villes et de forêts. De manière surprenante, notre étude n’a pas montré de réponses différentielles au cadmium entre ces deux populations concernant les ouvrières et nous n’avons pu tester notre hypothèse initiale que sur les mâles. En revanche, cette dernière étude met en lumière les limites à la résilience des sociétés d’insectes, qui pourraient être sujettes à davantage de stress et de manière plus chronique par rapport aux individus solitaires. Plus globalement, cette thèse ouvre la voie à reconsidérer le rôle de la taille chez les insectes sociaux et la place que prennent les intérêts individuels dans sa détermination. L’amélioration en profondeur des connaissances sur les déterminismes générant la diversité de taille, notamment via la génétique et génomique, aidera à la distinction entre intérêts du groupe et/ou des individus et ainsi à déterminer plus finement le rôle de la taille chez les insectes sociaux.
Article
Solenopsis japonica, which is belonging to Formicidae in Hymenoptera, is a native ant species in Korea. However, it had not been studied for cold hardiness of S. japonica to understand on its overwintering mechanisms in field so far. Cold tolerance on developmental stages was measured at different cold temperature with various exposure times. Workers showed more survival at 5°C and 10°C compared with other stages and elevated cold tolerance when workers were exposed at 15°C for more than 12h incubation as a rapid cold hardening (RCH) condition. RCH treatment not only increased survival of workers at cold temperatures, but also decreased supercooling point (SCP) and freezing point (FP). RCH group increased the survival rate by 44% at 10°C compared with Non-RCH group. SCP and FP were depressed from -10.0 to -14.2°C and from -11.3 to -15.3°C, respectively, after RCH treatment. Cold temperature increased expression level of cold- and stress-related genes such as glycerol kinase and heat shock protein. These results indicate unacclimated cold tolerance of S. japonica and its acclimation to low temperature by RCH.
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An account is given on some aspects of the biology of crazy ant Paratrechina fulva (Mayr). The number of larval instars for the male and worker castes were determined using a sample of larvae collected from the field. Head width and body length were measured; workers went through three larval instars while males did it through four. Three kinds of experimental colonies hexagynous, trigynous and monogynous were set up. The immature development of workers and the growth of a colony under laboratory conditions were studied. The mean duration of egg, larva and pupa was 16.2, 10.8 and 12.2 days respectively. The total immature development took from 23 to 50 days with a mean of 39.2 days. The highest production of brood was obtained in the hexagynous colonies. The highest production of eggs was reached faster in the polygynous colonies In contrast with the monogynous, while the maximum number of larvae and pupae was obtained towards the end of the observation period for all of the colonies. Brood mortality was higher during the incubation period and it reached an average of 70% for the monogynous colonies, this percentage was lower in the development of larvae to pupae reaching nearly 50% for the three kinds of colonies. Significant differences were found between the mortality percentages of larvae during incubation for the three kinds of colonies studied, specifically between the monogynous and hexagynous colonies. The polygynous colonies therefore proved to be more stable experimental units, showing a lower percentage of mortality of larvae after incubation and, although no significant difference was found, polygynous colonies were more successful in rearing brood to the pupal stage and they reached and maintained a pupae/eggs rate of at least 50% faster than the monogynous colonies.
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We investigated the roles of habitat fragmentation and the invasion of an exotic species on the structure of ground-foraging ant communities in 40 scrub habitat fragments in coastal southern California. In particular, we asked: how do fragment age, fragment size, amount of urban edge, percentage of native vegetation, degree of isolation, and the relative abundance of an exotic species, the Argentine ant (Linepithema humile) affect native ants? Within these fragments, Argentine ants were more abundant near developed edges and in areas dominated by exotic vegetation. The number of native ground-foraging ant species at any point declined from an average of >7 to <2 species in the presence of the Argentine ant. Among fragments, a stepwise multiple regression revealed that the abundance of Argentine ants, the size of the fragment, and the number of years since it was isolated from larger continuous areas of scrub habitat best predict the number of remaining native ant species. The Argentine ant was found in every fragment surveyed as well as around the edges of larger unfragmented areas. Fragments had fewer native ant species than similar-sized plots within large unfragmented areas, and fragments with Argentine ant-free refugia had more native ant species than those without refugia. The relative vulnerability of native ants to habitat fragmentation and the subsequent presence of Argentine ants vary among species. The most sensitive species include army ants (Neivamyrmex spp.) and harvester ants (genera Messor and Pogonomyrmex), both of which are important to ecosystem-level processes. Our surveys suggest that the Argentine ant is widespread in fragmented coastal scrub habitats in southern California and strongly affects native ant communities.
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The Argentine ant, Linepithema humile, is an invasive species with the potential to cause significant economic and ecological damage in New Zealand. Using published information on rates of development, we induced parameters for a cumulative degree-day model for each life-stage of the Argentine ant.A summary model suggested that complete development, from egg to worker, requires approximately 445 degree-days above a threshold of 15.9°C. Meteorological records of air and soil temperatures indicated a number of sites in New Zealand that fulfil this minimum temperature requirement on an annual basis. Maps based on soil temperature data indicated suitable conditions as far south as Central Otago, while air temperature data predicted a more limited northerly distribution in Northland and Hawkes Bay. Additional factors, such as microclimatic variation, thermoregulatory behaviour, biotic interactions and dispersal opportunities will also be important in determining the precise range limits of the Argentine ant in New Zealand.
Article
The Argentine ant, Linepithema humile (Mayr), is one of the most important invasive ant species in agricultural, urban and natural environments of Mediterranean climates worldwide. The following review is intended to summarize the important literature regarding the systematics, biology and control of this species. Special emphasis has been given to those abiotic and biotic factors that might be important in preventing the spread and impact of this tramp species.
Article
Human-caused biological invasions by an alien species are a worldwide phenomenon. They are particularly significant on isolated oceanic islands and represent a serious threat to endemic biota. The Argentine ant (Iridomyrmex humilis) has become established in portions of the high-elevation shrubland of Haleakala National Park, Maui, Hawaii, over the past 25 yr. This ecosystem lacks native ants but possesses many locally endemic and rare anthropod species. Pitfall trapping and under-rock surveys were conducted to determine the effects of I. humilis on the local arthropod fauna. More than 180 taxa were sampled, mostly Arthropoda. Presence of the Argentine ant is associated with reduced populations of many native and non-native anthropod species, including important predator species and major pollinators of native plants. Effects of ant invasion were particularly severe at higher elevations of Haleakala volcano where endemic species normally exist at low densities. Some taxa, primarily alien species, were more abundant in the presence of ants. Invasion of the Argentine ant has locally reduced the abundance of many endemic species in the shrubland ecosystem. Although the spread of this ant species is slow, I. humilis appears to have the potential to invade a much larger area of Haleakala National Park than it now occupies. Active management of Argentine ant populations will be necessary if the endemic fauna is to be preserved.
Article
Hypotheses concerning community-level vulnerability to invasion often emphasize biotic interactions but fail to consider fine-scale variation in the physical environment. In this study, the interplay between interspecific competition and abiotic factors is examined with respect to whether scrub habitats in southern California become invaded by the Argentine ant (Linepithema humile). Argentine ants penetrate further into and attain higher abundances in mesic scrub fragments than they do in xeric scrub fragments. Probably as a result, native ant richness is lower in small (