Life cycle. The
scarce data noted below probably do not reflect the variation to be found
between populations as northern as that from Warsaw (Poland) and those
from Iran. As compared with other Lasius species, the
sexuals appear earlier in the year: as early as March, within heated
buildings in Budapest (Andrásfalvy, in litt.). In three studied
populations from NE Spain,
year shows remarkably similar duration, beginning in early March
until late November, when certain colonies in protected zones are still
Daily activity. In two Spanish populations the ants remain active
for 24 h/day from May to late
September, with temperature controlling the
Food. This ant seems to be
highly dependent on aphid honeydew. In North-east Spain, during the
early season, when leaves are still lacking on deciduous trees or tree aphids are
scarce, this ant constructs
over small herbs protecting stem
and root aphids. In the full season ants visit aphids on different tree
species in huge numbers (video: 13''; 2,58MB.View/download: 7,81MB) and in rare instances individuals are seen
carrying small prey (collembola,
psocoptera). Ants are active throughout the entire day and aphid tending lasts for 24
h/day, from late April to late October, imposing a non-negligible cost on
the energetic budget of individual trees. Preliminary quantitative measures
indicate that ants can extract a mean of 250 cc honeydew per month on holm oak (Quercus ilex) and as much as 950 cc honeydew per
month on poplar trees (Populus nigra).
In a recent study (Paris & Espadaler 2009) food collection
performed by the
invasive ant Lasius neglectus and by the native ant L. grandis
was compared. The invasive ant collected 2.09 kg of honeydew per tree
while the native ant collected 0.82 kg. The aphid Lachnus roboris
was visited by both ant species. In holm oaks colonized by L.
neglectus, aphid abundance tended to increase and its honeydew
production increased twofold. The percentage of untended aphids was
lower in holm trees occupied by L. neglectus. Tending ants may
also prey on insects: the native ant workers carried more insects than
the invasive ant. Both ant species preyed mainly on Psocoptera and the
rarely tended aphid, Hoplocallis picta. We conclude that the
higher honeydew collection achieved by L. neglectus was the
consequence of (1) its greater abundance, which enabled this ant to tend
more Lachnus roboris and (2) its greater level of attention
towards promoting an increase of honeydew production.
condition and behaviour. Nuptial flight seems to be absent. In a single
instance alate males and queens were found in a spider net on a house wall
(Seifert 2000: 178), although this is not a definite proof of flying
behaviour. Except for this case, sexuals have never been detected flying out
of the nest. Intranidal mating, thus, is probably the rule (Van Loon et
al. 1990; Espadaler & Rey 2001).
Depending on the populations, colonies are very difficult to delimit as they
may coalesce and integrate a supercolony occupying continuous areas, as
large as 17 ha. In urban areas the colonies are considerably split and may ocupy a
single tree and up to 3600 ha. Finding many dealate queens (polygyny) in a nest is a key
diagnostic characteristic of this species, the single polygynous European
Lasius (s.str.). This biological aspect is very probably the best way to
identify it, although it is advisable to verify with the morphology. The
number of queens depends on colony size. Queen number, estimated by queens
found under stones, is about 35500 in the supercolony of Seva. Using
soil cores, worker number for that population in May 2002, was estimated
as 1.12 x 108 (Espadaler et al. 2004). The species merits the
qualification of unicolonial.
interpopulation relationships show the usual trait already known for
unicolonial ants: a reduced level of agressiveness, though some non-native
populations show higher levels of aggression in lab tests. Laboratory
tests on aggression should be refined to be fully applicable to this light-avoiding ant.
Have a look at its less than stressful tactics (video: 1' 17''; 3.07MB.
View/download: 2.98MB) and
compare with the much more aggressive Argentine ant (video: 1' 20''; 3.01MB.
highly aggressive against three native
1909, L. emarginatus (Oliver,
1992), expressed as a higher attack rate of
L. neglectus and
behavioural dominance throughout the aggressive encounters. Attacks of L. neglectus
were performed fastest and most frequent against L.
grandis, and also the highest antennation frequencies were observed in
encounters between these two species. This could be due to the largest
difference in body size, or due to a greater overlap in ecological niche
between L. neglectus and L. grandis compared to the other
two native species
(Cremer et al. 2006).
Nesting habits. The
areas occupied furnish a wide array of possible nesting sites:
temporal refuges with aphids at the base of herbs,
Nesting habitat. Non-native
populations of this
ant are usually related to human-modified habitats -ranging from purely urban
of a supercolony
to be much helped by the progresive urbanization of lots. This development
usually implies the cutting and burning of all natural vegetation but
trees. The planting of grass and continuous irrigation of grass that
follows favours the establishment of the ants.
a map showing the area of
the Debrecen supercolony
from 1998, 2000,
presence of different ant species'
entrances was mapped.
The expansion of
in space and time.
It seems that L. neglectus spreads fastest on paths, and does not
spread rapidly in shady and cool areas occupied by coniferous bushes.
The data suggest that the relative
1758) is more impacted by the invasion of L. neglectus than Tetramorium
cf. caespitum (L.,
1798) and Lasius fuliginosus (Latreille,
1798) were able to defend their territory
recent experimental research by Ugelvig & Cremer (2007), using L.
neglectus from four populations (Bellaterra, Jena, Seva, Volterra)
is the first demonstration of contact immunity in social Hymenoptera.
Social contact with individual workers that were exposed to a fungal
parasite (Metarhizium anisopliae var. anisopliae) provided
a clear survival benefit to non-treated ants, upon later contact with
the same parasite. Behaviour was also affected: brood care was absent in
infested ants whereas naive nestmates increased brood-care activities.
The collective behavioural and physiological prophyllaxis work to
promote the immunity of the society and to counteract the high risk of