is a genus of bees in the family Apidae
, subfamily Apinae
, and tribe Eucerini
– the long-horned bees.
As in most members of the tribe Eucerini
, the antennae of males are very long. Old World Eucera
can be identified through having five or six maxillary palpomeres
, with the first flagellomere
shorter than the scape and the clypeus
protruding in front of the compound eye
by at least the width of the eye in side view. These characteristics are found in both sexes. Additionally, the males have convergent carinae on their sixth ventral abdominal segment (sternite
species nest in the ground.
have a thick layer of fur and are dark in color. They have a protuberant clypeus
and are typically around 0.4 to 0.7 inches long. The size of bees in the genus Eucera
range from 11–18 mm. When emerging from nests, an immature Eucera nigrilabris
male will be somewhat red in color and a bit sluggish. A mature Eucera nigrilabris
male will appear grey in color and more active.
In Eucera berlandi
, males have long antennae
containing three times the amount of neuron
s for olfaction and ten times more pore plates than females.
. Research shows that the Eucera
complex originated in the Nearctic
region in the late Oligocene
and dispersed twice. The first dispersal having occurred as far as 24.2-16.6 million years ago during the warmer summer season and later again 13.9-12.3 million years ago during the springtime, allowing Eucera
to thrive in cooler regions.
belongs to the tribe Eucerini
and makes up roughly 50% of the tribe. Historically, the genus had 219 species classified in five subgenera, of which 78 species were known from Europe. However, six genera have recently been added to the genus Eucera
as new subgenera: Tetralonia, Peponapis, Syntrichalonia, Cemolobus, Xenoglossodes
In the Middle East
are active in the months of February to May.
have a spring flight season.
are solitary bees that nest within the ground. They tend to nest in areas that are composed of clay or sand. It is a characteristic of all bees of the genus Eucera
to have vertical and elongated cells within nests. There are around two to three cells per nest, which are found branching off of the main tunnel. In Eucera nigrilabris
, each tunnel harbors four to six cells. The first few cells are false cells and are not used for reproductive purposes. The cells below the false cells are used to lay eggs. Also, the entirety of the tunnel is lined with wax. For nesting, Eucera nigrilabris
prefers soil of lower sodicity
and salinity that has low calcium carbonate concentrations. They make lined nests that are about 85 cm into the ground. There has not been any observed occurrences of kleptoparasitism around Eucera nigrilabris
nesting sites. Eucera palaestinae
use their Dufour's gland
to secrete a mixture of hydrocarbon
s, methyl esters, and unsaturated fatty acids which provide the nest with an odor. This odor helps the bees locate their home when living in a dense aggregation of nests.
is known to fall victim to sexual deception by Ophrys leochroma
flowers that mimic the sex pheromone
s of female bees. Eucera palaestinae
live in dense nest aggregations with males emerging from their nests in the ground about a week before the females to take a look around the nesting site. Once the females emerge, males of the species will engage in aggressive competition to mate with them. Shortly after mating, the female becomes unreceptive. The initial attraction towards a female is by sight, but there is additional research suggesting that virgin females are distinguished by their specific scent and therefore are sought after more aggressively. It is thought that the cause of this sex attraction is due to small glands located on tergites
on the abdomen. In Eucera nigrilabris
, the males also emerge a few days earlier than females. Once the female emerges from the nest, males will fight with each other to mate. Mating time in this species occurs for 3–6 minutes, and once the female has mated, she becomes unresponsive.
can be generalists or specialists in foraging preference. They are able to pollinate both agricultural and naturally occurring plants. They pollinate plants in the deserts of Israel and the Mediterranean. Eucera,
like other efficient foragers, avoid going back to the same food source after it has been previously depleted. Research suggests that Eucera
use a combination of reward-based-patch-leaving rule and scent marking strategy to avoid returning to previously visited sites. Eucera
resemble bumblebees in this matter but it is believed that they use different strategies (bumblebees use a numerical strategy) suggesting that the difference in strategies may reflect the lower learning capabilities of solitary bees like Eucera
when compared to the social bumblebee. Eucera cinerea
has specialized thick bristles that curve and are used for foraging for pollen within flowers that have hidden anthers. Eucera
from southwest France are known to mainly forage from Fabaceae
are known to be specialists for squash plants, such as Cucurbita pepo
. Peponapis pruinosa
specializes on squash plants, and so the current distribution of this species in North America is due to the expansion of plant cultivation throughout North America. The species moved from Mesoamerica
into the more temperate regions of North America.
, similar to the rest of the tribe Eucerini, are solitary by nature. In some highly eusocial bee species, such as honey bees, males are raised and fed in their colonies. Males of Eucera
live their lives independently.
do not produce or respond to alarm pheromones as social bees do. Social bees are able to identify and avoid inflorescences that have the smell of dead bees of their species. This is possibly due to injured social bees releasing signals known as alarm signals to warn others of danger. Eucera
do not showcase this behavior of avoiding inflorescences marked by dead bees and instead respond similarly to flowers that have predation alarm signals and flowers that do not have such alarm signals.
The bee genus Nomada
, a genus that typically lays their eggs in the nests of other bees, is most likely to kleptoparasitize Eucera
List of Eucera species