why-dont-bees-fly-at-night

Why Don’t Bees Fly At Night?

Bees are among the many insects that are considered to be beneficial to our environment. Their ability to cross-pollinate has given us different plant species and a variety of flowers to enjoy. We owe these creatures many thanks because they pollinate one-third of the food we consume each day. Most of the fruits we enjoy today rely on the bees ability to pollinate. Without them, we would suffer a tremendous food shortage. They may be small but they have a very important role to play in our ecosystem.

Let’s ask ourselves, do bees fly at night or why don’t bees fly at night? Most species of bees are diurnal and fly during the day. However, there are many species that are able to fly during low light and at night. This is called crepuscular. Entomologists found that bees don’t fly during the night because it is difficult for them to see and avoid obstacles during the night. Nocturnal bees are much more rare.

Depending on the species, there are bees that are able to fly during dark or at night time. Some species prefer low light settings rather than complete darkness while others do venture out the night when conditions permit them. Some prefer to fly out during dawn to avoid the heat of the sun and some are nighttime foragers. These species will be discussed further into the article.

Classification Of Bees According To Day or Night Flight Habits

We can separate the bees into categories or types depending on when they collect nectar and pollen. Nocturnal is when they are active at night, crepuscular; when they are active during low light (dusk and dawn) or diurnal; when they are active during the daytime.

Nocturnal

Bees that belong in this category have the ability to fly at night. Most bees that belong to this type are from tropical countries. The wasps which are a close cousin of bees have also adopted this type of behavior. They both have the ability to forage and fly through the forest back to their nest without problems.

There is one known family of bees that are considered nocturnal and they are Megalopta atra. A specific species from the Panama Highlands called the Halictidae; Augochlorini and the Indian Carpenter Bee have been found to fly and forage even through the darkest of night, without any aid of moonlight.

The Lasioglossum (Sphecodogastra) texana or sweat bee as many call it, is a species of bee that has the ability to go out and forage during the night with the aid of adequate moonlight. These species have been studied and are found to be capable of nighttime flights during half-moon and full moons.

Crepuscular

Bees from this category are able to forage and fly during low light settings. These bees go out and are more active during dusk or dawn. It is said that they prefer to fly during these hours to avoid the scorching heat of the sun since most of the bees from this category are tropical species. To make it very specific, there are at least four up to seven families of bees that are recognized to have nocturnal or crepuscular flight and foraging capabilities. These are the following:

  • Colletidae
  • Andrenidae
  • Halictidae
  • Apidae

Species known to be crepuscular in nature are below:

  • Xylocopa tabaniformis
  • Xenoglossa fulva
  • Ptiloglossa guinea
  • Ptiloglossa jonesi
  • Ptiloglossa arizonensis
  • Caupolicana yarrow
  • Caupolicana ocellata
  • Xenoglossa fulva
  • Martinapis luteicornis
  • Peponapis sp.Lasioglossum (Sphecodogastra) galpinsiae
  • Megalopta genalis

Diurnal

Most species of bees belong to this category. These bees are active during the day and docile during the night. Bees that are found in areas where the temperature drops significantly at night tend to experience less bee activity at night and bees from tropical countries are the ones that produced species of nocturnal type. Most honeybee species are from this category but there are exceptions. The bee family Lasioglossum (Sphecodogastra) texana has two specific species that can fly during the night with the aid of moonlight.

These species are:

  • Giant Asian honeybee Apis dorsata
  • African honeybee Apis mellifera adansonii

What makes the night flying bees different?

All bees possess five eyes. Three of those eyes called ocelli are simple eyes that have one lens just like a human’s eye. These three eyes are located at the center-top of the bees head. The main purpose of these ocelli is to sense ultraviolet, polarized and infrared lights. They aid the bees’ orientation but does not provide any form or image. These ocelli eyes are the ones that can detect when a bee is being approached from above. Then there are the other two eyes called the compound eyes which is actually the main eye of the bee that helps them see patterns to identify the plant they are targeting. These eyes have the ability to see all around simultaneously (up, down, left, and right) because of the 6,900 hexagonal facets it has.

Night time bees have evolved these eyes to adapt to the darkness. They are much larger than the average diurnal bees allowing them to navigate the forest during night, dawn or dusk. You can see the difference in size better when the ocelli eyes are measured.

A great example is the size of the ocelli of an Indian Carpenter Bee (Xylocopa tranquebarica) which is a millimeter across versus the size of the ocelli of X. ruficornis, which is a diurnal bee (daylight bee) measuring less than half the size.

Why do some bees forage at night?

A number of reasons can be attributed to why some bees have evolved into nocturnal or crepuscular bees. These reasons are the following:

  • Bees that live in areas where it is very dry chose to fly during the times when the sun is not shining to lower down their water consumption. This especially evident for species found in tropical countries.
  • The abundance of nectar and pollen from nighttime flowering plants might have spurred the evolution of these bees. They needed to take the opportunity of gathering as much food as they can and so their eyes adapted to low light settings in order to seize the chance. Some bees would go out during the dawn to be able to gather the abundance of nectar and pollen of the undisturbed flowers.
  • As mentioned before, most bees are diurnal (daylight bees) which means that competition during daytime is a problem. Nocturnal bees have less competition, therefore, is able to gather more pollen and nectar without battling with other bees, butterflies, beetles, and other insects. They do, however, need to watch out for bats and moths.
  • Nocturnal and crepuscular bees avoid the daytime predators and parasites that threaten their daylight flying brothers and sisters.

Conclusion

As you can see, bees are either, diurnal (daytime), crepuscular (dawn or dusk) or nocturnal (night) in nature. The common bees we know are part of the diurnal type which chose to forage and fly during the day. The crepuscular and nocturnal bees are evolved species of bees which goes out and collects food during nighttime, dusk or dawn. These bees have developed better and larger eyes to let them see in a low-light environment and to better navigate the forest at night. Some diurnal species have the ability to fly at night with the aid of adequate moonlight.

Nocturnal bees have chosen to gather their food at night to avoid predators, lessen competition and also to conserve water. These little creatures have proven how important they are by being dubbed as a keystone species of our planet. This means that without them, major ecological crises will be felt all over the world.

Related Questions

Do bees ever sleep?

Yes, they do. They actually sleep between five to eight hours a day. Bees are hardworking insects and for a very good reason. Without them, most of the flowering plants will be left un-pollinated and bear no fruit. Honey bees work day and night but in a shifting schedule. You can tell that a bee is sleeping when they stop moving their antennae, their wings rest on their body and their rear end and upper body droop a little. Sometimes they also fall over and needs the help of their fellow bees to not fall off the hive during sleep.

Why are honeybees considered a keystone species?

They are considered as a keystone species because they are responsible for the pollination of 80% of flowering plants and crops of the world. Once extinct, an estimated fifty percent loss of plant species will result. Seed production will decrease dramatically and certain plant species will cease to exist. Fruit bearing trees and plants will have a hard time producing fruits. The ripple effect of bees extinction can extend up to humans experiencing food shortage.

What are a bees defense mechanisms?

Other than the sting, they also possess other defense mechanisms when attacked. During a hive attack, honey bees have the ability to heat their abdomens up to 100 degrees Fahrenheit cooking whatever predator enters their hive. They also have a defense mechanism that confuses predator insects, they call it the shimmery defense. This is when honey bees shimmer by flicking their abdomens up all at the same time creating a shimmering effect that confuses predators such as wasps and hornets.

2 Comments

  1. Avatar
    Andrew Wheater

    Good Morning,

    I’d like to congratulate you on a superb website. There is lots of useful content here and I was both impressed and learnt a great deal on the topic of beekeeping.

    Andrew.

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