Lasioglossum hemichalceum facts for kids
Quick facts for kids Lasioglossum hemichalceum |
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| L. hemichalceum | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
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| Order: | |
| Superfamily: |
Apoidea
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| Family: |
Halictidae
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| Subfamily: |
Halictinae
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| Genus: |
Lasioglossum
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| Species: |
L. hemichalceum
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| Binomial name | |
| Lasioglossum hemichalceum (Cockerell, 1923)
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The Lasioglossum hemichalceum is a type of sweat bee. It is found only in Australia. These bees are special because many unrelated females often share one nest. This behavior is called "communal." They build their nests underground.
L. hemichalceum bees usually start new colonies in the summer. They produce their young from late November through early spring. These bees are not aggressive towards each other. As a colony grows, each female bee can still have as many babies as before. This is different from many other bee species.
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About the Lasioglossum hemichalceum Bee
What Kind of Bee Is It?
Lasioglossum hemichalceum is part of a large group of bees called Lasioglossum. It belongs to a smaller group within that called Chilalictus. There are almost 150 other species in the Chilalictus group, and all of them live in Australia. Other bees in the Lasioglossum genus include Lasioglossum malachurum and Lasioglossum zephyrus. Some Lasioglossum bees in other parts of the world can live alone, in groups, or in semi-social ways.
How to Identify This Bee
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Lasioglossum hemichalceum bees have medium-long antennae, which are often off-white. They also have a triangular head. Many are dull black, but some might have hints of purple, green, or copper colors.
Male bees are usually thinner than females. They also have less hair on their back legs, as they don't carry pollen. Female bees are typically 4.7–5 mm long. Their heads are wider, about 1.5–1.6 mm across. Males are a bit shorter, about 3.8–4.7 mm long. Their heads are narrower, about 1.3–1.5 mm wide.
The legs of L. hemichalceum are usually dark brown or black. Sometimes, they can be reddish-brown. Males and females have similar colors. Since these bees live communally, there are no "queens" that look different from the other females. Almost all females look the same.
Two Types of Males
There are two types of male Lasioglossum hemichalceum bees. Some males are of typical size. Others are called "macrocephalic," meaning they have a very large head and strong jaws. Macrocephalic males have wider heads than both females and smaller males. They are also heavier when they are pupae (the stage before becoming an adult bee). Small males usually live away from the nest. Macrocephalic males tend to stay inside the nest.
Where They Build Their Nests
Female Lasioglossum hemichalceum bees build their nests underground. They dig tunnels and carry the removed dirt to the surface. When a colony starts, females dig many tunnels. However, as winter approaches, they dig less. They work on their tunnels independently, not coordinating with each other.
Where These Bees Live
L. hemichalceum bees are found only in certain parts of Australia. You can find them in New South Wales, Victoria, and Queensland. In southern Australia, their home has mild, wet winters and warm, dry summers. Their nests are almost always built underground by different groups of egg-laying females.
Life Cycle of a Colony
Starting a New Colony
New colonies usually start in late November and finish by early spring (February or April). This happens after the females have spent the winter. The bees have two choices for starting a new home. They can find soft ground and dig a brand new nest. Or, they can reuse a nest from the year before, which happens about 40% of the time. Sometimes, they even add new parts to old nests.
New nests are created even if other colonies are already using the same nest area. One female starts digging, and others join her. A nest can grow to have over 100 bees, with more females than males. It's important to remember that these females are not related to each other. This is different from other communal or eusocial bee species.
Colony Growth and Decline
During the colony's active time, the females that lay eggs will raise two groups of young bees, called broods. The first brood is raised by the mothers. The second brood is raised by both the surviving mothers and their daughters from the first brood. However, the number of broods depends on the weather. For example, if it's rainy, they might only raise one brood instead of two.
New nests are often started between the first and second broods. This means the colony starting and nesting cycles happen together. Once eggs are laid, the egg-laying females build individual cells for each egg. Each cell gets a ball of nectar and pollen. The egg is laid on top of this pollen ball, and then the cell is sealed. The size of these pollen balls affects how big the adult bees will be. The pupa stage alone lasts 18 days, but the whole cycle from egg to adult takes about 6 weeks.
Colony decline happens in the summer, after egg production stops and before the bees prepare for winter. Because female L. hemichalceum move between different nests, more than one nest exists at a time.
Bee Behavior
Living Together (Communal Behavior)
Lasioglossum hemichalceum bees show typical communal behavior. This means many females share the same nest. Each female takes care of her own young, and all females can lay eggs. Their colonies are often small and well-hidden.
These bees share nectar with each other by mouth-to-mouth feeding, called trophallaxis. They are very cooperative, even though most colony members are not related. This shows that they interact well with non-relatives. Unlike most communal bees, L. hemichalceum don't usually stay in the same nest for many generations. However, they might reuse a nest later in their lives.
No Bosses Here! (Egalitarian Behavior)
Because L. hemichalceum is a communal species, they act in an egalitarian way. This means there's no clear leader or special jobs for different bees. All females can reproduce. This is likely why they are so cooperative and equal.
They rarely show aggressive behavior. They don't treat bees differently based on whether they are family or just nestmates. So, they don't fight based on who is related to whom. This equal system is very different from bees like L. zephyrus, which have a clear division of labor.
Mating Habits
L. hemichalceum males have different mating behaviors depending on their body type. Smaller, typical males mate away from the nest. This helps keep the bee family tree diverse. However, the macrocephalic males (with big heads) stay in the nest and mate with females there.
To mate with females in the nest, macrocephalic males will fight each other. These fights can be very serious, even deadly. Since macrocephalic males can mate with several females, their offspring will be related. Because of this, females often leave their home nests to find mates elsewhere. This helps reduce how closely related the bees in one colony are. Females usually spend the winter and start reproducing in the spring. Sometimes, if food is scarce or there are many predators, a female might choose to stay and mate in the colony, but this is less common. If a female needs to leave the nest to find food, it's a good chance for her to also find a mate outside the colony.
Family Ties (Kin Selection)
How Related Are They?
How related L. hemichalceum bees are depends on their relationship. Since they are communal, there isn't a "queen" and "worker" system to look at. Scientists measure how related they are using a value called "mean relatedness" (r).
For mothers and daughters, the genetic relatedness is low compared to other bee species. Even though mothers and daughters share some genes, only about 11% of young daughters share a colony with their mother. This means most young females don't have their mother nearby. This number is even lower for mother-son relationships (r=.125). In fact, only about 20% of all young bees in a colony have any close adult relatives present. These numbers suggest that parents care for young bees generally, without focusing only on their own offspring. This is probably why females act kindly towards all other bees. Bees switching nests and moving around also makes adults and their relatives less related within a single nest.
However, there's a big difference in how related sisters are compared to brothers and sisters. L. hemichalceum bees try to avoid inbreeding (mating with close relatives). This is because of their special sex determination system. If family members breed, male offspring could be haplodiploid (normal) or diploid (sterile). So, females try very hard to avoid inbreeding.
This lack of inbreeding affects how related siblings are. There are many full sisters within a colony among young bees. This might be because young females don't need to avoid their female siblings as much as they avoid male siblings to prevent inbreeding. Similarly, sister-brother relatedness is low within the same nest because females tend to leave if male relatives are nearby.
Pros and Cons of Living Together
Living communally in a large colony has many benefits and drawbacks for L. hemichalceum. Many bees live with unrelated individuals (about half of adult females don't have daughters or sisters nearby). But they gain many advantages.
One main benefit is constant care for larvae (baby bees) and other young. It takes about six weeks for a larva to become an adult. Having other adults nearby to guard the nest greatly reduces the risk of predators like ants. Another benefit is "life insurance." Foraging for food is risky. If a mother bee is killed while foraging, her young will be protected by other colony members. So, forming a larger colony (a typical colony has about 200 bees) is good for protecting the young.
However, there are also disadvantages. While adult L. hemichalceum bees are good at keeping unwanted predators away, they don't actively defend the nest by fighting. This makes it less helpful to be in a large colony when active defense is needed. Also, there can be "cheaters" who take advantage of the colony's protection without contributing much. Scientists think that communal protection of unknown young might prevent this, but they are still studying this idea.
Recognizing Family
While it's thought that L. hemichalceum bees can recognize their relatives, it's not fully proven. At first, scientists thought their cooperative behavior and sharing of food with both relatives and non-relatives meant they couldn't tell family apart. However, now it's believed that females simply don't give special treatment to their own family.
This is shown by their lack of guarding against unknown bees and females moving between different nests. This attitude of accepting everyone has led scientists to think that either these bees don't have ways to recognize family, or they don't react to those cues. Also, while there are no differences in behavior based on relatedness, there are differences linked to groups of several nests. This suggests that environmental clues might influence their behavior.
Bee Behavior: No Fighting!
Unlike other Lasioglossum species, L. hemichalceum bees rarely show aggressive behaviors towards each other. Aggressive behaviors usually include lunging or curving their bodies into a "C" shape while pointing their stinger and jaws at another bee. The "C-posture" was seen in only about 19% of conflicts, and lunging even less often. This shows that even though they can be aggressive, they choose not to be. This lack of fighting is a big difference between L. hemichalceum and its close relative, L. zephyrus.
How Food Affects Male Bees
For L. hemichalceum, the food a larva gets is a major factor in how male bees develop. When a female bee gets ready to lay eggs, she first builds individual cells. She puts small pollen balls (a mix of nectar and pollen) into these cells. The size of the cell and the pollen ball seems to affect whether a male bee becomes macrocephalic (big-headed) or a normal male.
These factors are connected. For example, the size of the cell affects how much nectar and pollen the female gathers, which then affects the size of the pollen ball. The size of the pollen ball also affects how the bee develops. Females usually place fertilized female eggs on pollen balls that are bigger than those given to males. However, scientists think that macrocephalic males might happen if females accidentally place unfertilized eggs (male eggs) on pollen balls meant for female eggs. By giving males extra food, they can become heavier as pupae and grow into larger, bulkier adult males. So, the development of different male types in L. hemichalceum is thought to be influenced by cell size and pollen ball size, not just genetic differences.
Images for kids
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L. hemichalceum
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Preserved full body specimen of Lasioglossum hemichalceum
