Venomous and poisonous arthropods: what makes them different?

After talking about venomous mammals, fishes and lizards, ‘All you need is Biology’ brings you this post about venomous and poisonous arthropods. We will try to explain you what makes them different and which arthropods produce some kind of toxic substance (and how they do it). It will probably surprise you!

Venomous vs poisonous animals

Although some people normally use these words interchangeably, they really mean the same? The answer is NO.

A venomous animal develops specialized organs or elements (such as fangs, teeth or stings) to actively inoculate venom inside the body of their victim as an offensive or defensive mechanism. On the other hand, a poisonous animal does not develop these type of organs, but specialized tissues or glands that produce toxins that are released passively as a defensive system; others acquire these substances from their diet. Sometimes, the toxin is not produced in any specific organ, but integrated within body tissues as a defense against predation.

Despite these differences, once in the body venoms and toxins can cause similar damage, which depends on their mode of action, the assimilated amount and the victim’s features. In humans, effects caused by these substances range from irritation, inflammation or redness to severe systemic damage in cases of powerful poisons.

Venomous and poisonous arthropods

Arachnids

Arachnids (subphylum Cheliceromorpha) include two of the better known venomous arthropods: spiders and scorpions. Both groups develop specialized organs to inoculate venomous substances which use either to hunt and defend themselves against predators or potential enemies.

• Spiders

The specialized organs for venom inoculation in spiders are the chelicerae, a pair of preoral appendices typical of Cheliceromorpha which they use to grab the food. Spiders’ chelicerae, which are fang-shaped, are related to basal venom glands. These fangs have an internal duct that finish in a terminal opening through which venom is released and injected inside victims’ bodies like a hypodermic needle.

Spiders have the most evolved form of chelicerae: jackknife chelicerae. The two parts of the chelicerae come together like a folding knife, and when threatening to attack, the spiders rise the chelicerae and open the angle of the fangs.

Spider’s chelicerae. Public domain image (CC0) obtained from pixabay.

Some of the most dangerous spiders for humans are the Australian funnel-web spiders (genera Atrax, Hadronyche and Illawarra). Their venom is toxic to sodium channels, which results in the massive release of neurotransmitters.

“Funnel web spider” of the species Hadronyche cerberea. Have you noticed the drop of venom in its chelicer?. Picture by Alan Couch on Flickr (CC 2.0).

• Scorpions

The most distal part of the scorpion tail, the telson (an additional segment found in several arthropods), has become a venomous organ that ends in a stinger. Like chelicerae in spiders, telson in scorpions is related to venom glands that contain toxic substances.

Scorpion of the species Centruroides vittatus, common in the middle of EUA and in the north of Mexico. In red, telson ended in a sting. Public domain image (CC0).

Scorpion venom is usually rich in neurotoxins that alter both the central and the peripheral nervous system of the victim by dissociating the parasympathetic and sympathetic nervous systems. In humans, the effects of their sting vary from intense local pain (with minor inflammation) to cardiac arrhythmias and acute pulmonary edema, like in the Indian species Hottentotta tamulus, which is considered one of the most venomous scorpions in the world.

BE CAREFUL! Neither all arachnids nor related groups are venomous; e. g. harvestmen, camel spiders and whip spiders (Amblypygi) ARE NOT venomous.

From left to right: harvestman (Daniel Jolivet on Flickr, CC 2 .0), camel spider (CC 3.0) and whip spider (Geoff Gallice on Flickr).

Myriapoda

The subphylum Myriapoda is divided in two classes: Diplopoda (millipedes) and Chilopoda (centipedes), and both produce toxic substances.

• Millipedes

Millipedes, which have an elongated body composed of a lot of segments with two pairs of legs (rarely just one pair), are detritivores and inoffensive. However, they release toxins (alkaloids, benzoquinones, phenols) as a defensive mechanism to prevent predation. Some of these released substances are caustic and can burn the exoskeleton of other arthropods or cause skin and mucous inflammation in bigger animals.

Millipede toxins are produced inside repugnatorial or odoriferous glands and then excreted through small micropores located at both sides of the body when being crushed or feeling threatened.

At the first sight, micropores are difficult to see. Picture by Thomas Shahan on Flickr (CC 2.0).

TRIVIA: black lemurs from Madagascar (Eulemur macaco) grab and bite millipedes to stimulate their secretions, and then rub them all over their body. It is thought that lemurs cover themselves on millipede’s toxins since these work as insect repellent.

If you want to learn some more about this behaviour, don’t miss the following video. We recommend you to stay until the end…the final result will probably surprise you!

• Centipedes

Centipedes also have a segmented body like millipedes; however, each segment has just a pair of legs. While millipedes are detritivores, centipedes are carnivorous arthropods that hunt their preys actively. To do so, they have developed two large forcipules originated from the first pair of legs which can inject venom contained in glands in the trunk of the animal. They also bite when feeling threatened.

Forcipules of Scolopendra cingulata, by Eran Finkle (CC 3.0).

The Scolopendra genus causes the most severe injuries. However, despite causing an intense pain when stinging, almost all envenomations caused by centipedes spontaneously resolve without complications.

Insects

Despite their diversity, there exist just a few cases of venomous/poisonous insects (class Insecta).

• Beetles

Some beetle families (Coleoptera order), such as Meloidae, Oedemeridae and Staphylinidae (Paederus and Paederidus genera) contain toxins within their hemolymph which are released by compression as a defensive strategy against predators. These substances cause skin burns, redness and inflammation in humans.

Sptaphylinidae of the species Paederus littoralis, from Spain, France and Italy. Picture by Alvesgaspar (CC 4.0).

Meloidae and Oedemeridae hemolymph contain cantharidine, while the one of Paederus and Paederidus contains pederine, a substance that is exclusive of females of these beetles and of certain marine sponges, and which is thought to be produced by symbiont bacteria.

• Bugs

Although some bugs (suborder Heteroptera) are better known for being disease vectors, they also cause different types of skin injuries in humans due to the release of caustic and inflammatory substances as a defense when being compressed (e. g. Pentatomidae family) or by the injection of salivary enzymes that are normally used to kill and dissolve preys (e. g. Belostomatidae family).

Belostomatidae. Public domain image (CC0).

• Hymenopterans

Most of wasps, bees and ants (Hymenoptera order) produce toxins as a defensive mechanism. In most of those cases, females develop a stinger at the end of the abdomen resulting from the evolution of the ovipositor (Aculeata infraorder); however, there are also some groups that defend themselves by biting.

Ants (Formicidae family) usually attack by biting, but some species, such as those in the group of the fire ants (Solenopsis spp.) and the bullet ants (Paraponera spp., Dinoponera spp.), also have stingers like bees and wasps. Formic acid probably is the best-known toxin produced by ants, but is unique to the Formicinae subfamily; fire ants, for example, inject piperidine alkaloids. The sting of the bullet ants, which are distributed throughout center and south America, is considered the most painful sting for humans caused by an insect according to the Schmidt Index (which considers it to be as painful as a gunshot!).

Red ant of the species Solenopsis invicta (left, public domain image (CC0)) and bullet ant of the species Paraponera clavata (right, April Nobile / © AntWeb.org / CC BY-SA 3.0).

Females of most of bees and wasps within the Aculeata group develop an abdominal stinger. Their venom is usually rich in phospholipases, producing effects ranging from local inflammation to severe anaphylactic reactions (when suffering of hypersensibility or after being attacked by thousands of insects, as it has happened several times with the killer bee in America). The sting of the tarantula hawk (Pepsis formosa) from Mexico and southern USA, is considered the second most painful after the one of the bullet ant.

Pepsis formosa, a tarantula hawk. Public domain image (CC0).

• Butterflies and moths
  

A lot of butterflies and moths (Lepidoptera order) produce toxins either during their larval stages, adulthood or both as a defensive mechanism against predation.

Sometimes, caterpillars are covered by urticant bristles or hairs that cause skin lesions (erucism), as in the case of the pine processionary (Thaumetopoea pityocampa), a harmful plague for pines which is very spread in southern Europe and America.

Pine processionary caterpillar nest, by John H. Ghent (CC 3.0).

On the other hand, adults of some species, like those of the monarch butterfly (Danaus plexippus) and Zygaena spp., both showing flashy colors (aposematism, a type of animal mimicry), develop toxins within their corporal tissues to prevent predation. The monarch butterfly obtains these substances by feeding on toxic plants of the Asclepias genus.

Zygaena transalpina, by gailhampshire (CC 2.0).

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Have you found this information interesting? Do you know any other venomous or poisonous arthropod? Feel free to leave your comments below!

References

• Haddad Junior, V., Amorim, P. C. H. D., Junior, H., Teixeira, W., & Cardoso, J. L. C. (2015). Venomous and poisonous arthropods: identification, clinical manifestations of envenomation, and treatments used in human injuries. Revista da Sociedade Brasileira de Medicina Tropical, 48(6), 650-657.
• “What’s the Difference Between Poisonous and Venomous Animals?” de Smithsonian.org.

The main image is of public domain (CC0) and was downloaded from Pixabay.

Bees and wasps: some myths and how to tell them apart

Despite being part of the same order of insects (Hymenoptera), bees and wasps have well differentiated traits and habits; however, it is very common for people to confuse them. In this post, we will give some simple clues to differentiate between them, and deny some of the most common myths that revolve around these organisms.

Bees and wasps: how to tell them apart

Before differentiating them visually, we should start by classifying them.

Both bees and wasps are part of the Hymenoptera order, which are characterized by two pairs of membranous wings that remain coupled during the flight thanks to a series of tiny hooks (hamuli); in addition, they usually present antennae more or less long, of 9-10 segments at minimum, and an ovopositor that, in certain groups, has evolved to become a sting. Within this order, both bees and wasps are classified within the Apocrita suborder, which are characterized by having a “waist” that separates the thorax from the abdomen.

As for Apocrita, this suborder is traditionally divided in two groups: “Parasitica” and “Aculeata”, which we’ve already mentioned in the post “What are parasitoid insects and what are they useful for?“:

• “Parasitica”: very abundant superfamilies of wasps that parasite arthropods (chalcidoidea, ichneumonoidea, cynipoidea, etc.), except for the family Cynipidae (gall wasps), which parasite plants. None of these wasps have a sting, so no worries!
• “Aculeata”: includes most of the so-called wasps and bees (as well as ants), most of which have stings.

So far, we can see that there are a large number of parasitic wasps that differ clearly from the rest of bees and wasps with sting. If we continue to deepen, within the “Aculeata” we typically distinguish three superfamilies:

• Chrysidoidea: group formed by parasite wasps (many of them kleptoparasites) and parasitoids. The Chrysididae family (cuckoo wasps) is very popular due to its metallic coloration.
• Apoidea: includes bees and bumblebees, as well as the formerly known as “sphecoid wasps”, most of which have become part of another family of Apoidea (Crabronidae)
• Vespoidea: mostly formed by the typical stinged wasps (eg Vespidae family) and ants.

Cuckoo wasp (Chrysididae). Author: Judy Gallagher on Flickr, CC.

Simple keys to differentiate

After this review, many will think that this separation of wasps and bees is not so simple; and those of you who do will be right. While bees and bumblebees belong to a monophyletic lineage (this is, a group that includes the most recent common ancestor and all their descendants) and their characters are quite clear, the concept of wasp is somewhat vaguer.

Here are some basic morphological and behavioral traits to differentiate the most common wasps and bees. These traits are easy to spot in a simple way, and in the eyes of expert entomologists, they may be very general (there are many other complex characters that make it possible to differentiate them); however, they can be useful when you do not have much experience:

• Bees (and specially bumblebees) tend to be more robust and hairy than wasps. Wasps do not show “hair” and tend to be slender, with thorax and abdomen more widely separated.

Left: western honey bee (Apis mellifera); author: Kate Russell on Flickr, CC. Right: wasp from the genus Polistes; author: Daniel Schiersner on Flickr, CC.

• Most of bees present corporal adaptations for the collection of pollen, which they receive the name of scopa. In most, these are limited to the presence of many hairs on the hind legs. However, there are special cases: in the western honey bee (Apis mellifera), in addition to having pilosities, the tibias of the hind legs are very widened, forming a kind of blades with which they collect the pollen; on the other hand, the solitary bees of the Megachilidae family do not have pilosities on the hind legs, but a series of hairs on the ventral side of the abdomen.

Left: western honey bee (Apis mellifera) with the hind legs full of pollen; author: Bob Peterson on Flickr, CC. Right: Megachile versicolor, with the scopa in the ventral side of the abdomen; author: janet graham on Flickr, CC.

• Most wasps have chewing mouthparts (jaws retain their function), while in most bees mouthparts are lapping type, as we explained in the post “Evolutionary adaptations of feeding in insects”.
• Some wasps, especially certain parasites and parasitoids, present a much simpler wing venation, represented by a few marginal veins. This is the case, for example, of the families Chalcidoidea and Cynipidae.

Halticoptera flavicornis male, Chalcidoidea (a parasitoid wasp); author: Martin Cooper on Flickr, CC.

• If you see a slender hymenopteran with a very long “sting”, do not be afraid: it is probably the female of a parasitoid (eg a member of the family Ichneumonidae), and that long “sting” its ovipositor.

Ichneumonidae female of the species Rhyssa persuasoria; author: Hectonichus, CC.

• Many wasps fly with legs more or less extended because, with rare exceptions, they are hunters.
• As we approach a plant with flowers, we will observe a large number of insects flying and perching on them. Almost certainly, most hymenopterans we will observe will be bees, since all adults and almost all larvae are phytophagous (they feed on plant products), namely nectar and pollen.

Western honey bee. Public domain (Zero-CC0).

• If you’ve ever left food in the open, you must have seen a hymenopteran come to it. The larvae of most wasps are carnivorous, so adults take the least opportunity to catch prey for their offspring … or bits of something that you are eating.

Author: rupp.de, CC.

This is not over yet: myth busting

Now that we know how to differentiate them roughly, let’s confirm or deny some of the most common myths around bees and wasps:

• “Wasps do not pollinate plants“

False. It is true that bees play a very important role in pollination: their feeding based on the intake of nectar and pollen makes them visit many flowers and, in addition, they present many pilosities in which it is adhered. However, most adult wasps also ingest nectar, in addition to other foods. Although they do not present as many pilosities as bees, the mere fact of visiting flowers causes that their body comes in contact with pollen and part of it is adhered.

There is also the opposite case: some bees such as Hylaeus and Nomada (the latter known as cuckoo bees, kleptoparasite bees whose larvae feed on pollen stored in nests of other solitary bees) do not have adaptations for pollen transport, and their appearance is closer to that of a wasp.

Left: Hylaeus signatus male; author: Sarefo, CC. Right: solitary bee of the genus Nomada; author: Judy Gallagher, CC.

• “All bees are herbivorous, and all wasps carnivorous“

False. Although almost all bee larvae feed on pollen and nectar, while wasp larvae do on prey that adults hunt or parasite, there are exceptions. The larvae of gall wasps (Cynipidae family) feed on the plant tissue of the gall itself where they develop, whereas the larvae of a small group of bees of the Meliponini tribe (genus Trigona), present in the Neotropics and in The Indo-Australian region, feed on carrion, the only bees are known non-herbivorous.

• “Bees form colonies, and wasps are solitary“

False. There are both colonial and solitary wasps and bees. Honey bees are the most typical colonial bee, but there is an enormous diversity of solitary bees that build small nests in pre-established cavities or ones they dig. In the same way, there are also colonial wasps, like some of the genus Polistes (paper wasps) that build hives in which certain hierarchical roles are established (although they are usually smaller than those of bees).

• “All bees and wasps can sting“

False. The bees of the Meliponini tribe, also called stingless bees, have a sting so small that it lacks a defensive function, so they present other methods to defend themselves (biting with their jaws). In addition, females of some bees (eg Andrenidae family) do not present sting. Of course, all male bees and wasps have no sting, as that it is the modified ovipositor.

• “Bees die when they sting; wasps can sting several times”

Partly true. In honey bees of the species Apis mellifera, the surface of the sting is covered with a series of beards that give it the look of a saw, so that when removed, the sting is nailed to the surface of its victim, dragging behind it all the abdominal content to which the sting is adhered. In wasps, solitary bees and bumblebees, on the other hand, the surface of the sting is almost smooth or the beards are very small, being able to retract them and thus remove the sting without problems.

Sting of Apis mellifera; author: Landcare Research, CC.

• “Wasps are more aggressive than bees“

It depends. Wasps commonly nest anywhere, so people and other animals are more likely to come into contact with them. By contrast, bees often have preferences for certain places, usually more protected, not being so exposed. However, this is not always how it happens: the african bees, to which we dedicated a post, can nest almost anywhere and they are very aggressive!

• “Wasps are more colorful than bees“

False. In fact, partially false. Having no apparent hair, the color of wasps is usually more striking in general terms. However, there are genera of bees, such as the solitary Anthidium (which present a very striking abdominal coloration) or the orchid bees, which look similiar to wasps. In the same way, there are wasps of dark coloration and less jazzy.

Anthidium florentium male; author: Alvesgaspar, CC.

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Despite there are much more differences between bees and wasps, we hope these tips can help you to tell them apart…and to love them the same way!

REFERENCES

• Michener, C. D. (2000). The bees of the world (Vol. 1). JHU press.
• Landcare Research (landcareresearch.co.nz): Stings.
• United States Department of Agriculture (USDA): Wasp pollination.

Main images property of Kate Russell, CC (Left) and Daniel Schiersner, CC (Right).

 

The killer bee: the case that shook up America

In the ‘60s, American media picked up a case that shook up countries all over the world: hybridization of two types of honeybee gave rise to an aggressive, unstoppable and lethal new organism. The killer bee had arrived.

This little insect appeared on the front cover of numerous famous magazines and newspapers during a long time and it even assumed the main role in some terror films (such as “The Swarm”, 1978). However, when did fiction surpass reality? What’s true in this story? Keep reading to get the answers.

The origin of killer bees

The most famous honeybees belong to the species Apis mellifera, which is widely spread all over the world. All its subspecies are native to Europe, Africa and Asia, although some of them (specially the European ones) have been imported to different countries worldwide due to their value for crop pollination and honey production.

You can read the post ‘Family life of bees and beekeeping‘ to know more about this topic.

The breeding of honeybees (beekeeping or apiculture) is a widespread practice all over the world. In America, European honeybees were imported for this purpose. Author: Emma Jane Hogbin Westby, CC on Flickr.

The origin of killer bees underlies on the subspecies A. mellifera scutellata or African honeybee, native to Sub-Saharan Africa and southeast of Africa. Unlike European honeybees, these are very aggressive. In America, these bees hybridized with imported European or Western honeybees, giving rise to hybrid bees known as Africanised bees. These hybrids, along with native African honeybees and the descendants they gave birth in America, were colloquially named as killer bees.

Native range of distribution of the African honeybee. Source: UF/IFAS, University of Florida. Original illustration property of Jane Medley, University of Florida.

How and why did they spread over America? 

In the ’50, the importation of European honeybees to America was a frequent practise. However, while beekeeping had good results in the USA, it didn’t seem to work in South America because honeybees from Europe didn’t adapted well to tropical climate. Thus, in 1956, the Brazilian scientist Warwick Kerr suggested to import African honeybees to Brazil instead of the European ones in an effort to increase honey production. Then, the unique main problem he needed to solve was the aggressive nature of this subspecies. The main objective of Dr. Kerr was to obtain a docile variety of bees that was also productive in tropical climates by artificial selection and cross-breeding of the African honey bee (A. m. scutellata) with various European honeybees.

The project would had been a success if it weren’t for the fact that some swarms accidentally escaped quarantine. The experimental bees rapidly formed new colonies and began to hybridize with both wild and domestic European honeybees, giving rise to the Africanised honeybees which were more aggressive and less productive than Dr. Kerr expected.

These bees are currently located in almost all over the American continent. In the USA, they didn’t spread further north due to their tropical origins, so their range of distribution in North America is limited to the southern states of the USA.

The spread of the killer bee over America was fast, even reaching the southern states of the USA in a few years since they escaped. Source of the original illustration: Harvard University Press (86).

Analysing the killer bee

Morphology

At the beginning, beekeepers faced the difficult to differentiate the African honeybees from the European ones, because they look quite similar at first glance. However, exhaustive studies allowed to confirm the existence of, at least, two differences between them: both African and Africanised honeybees are slightly smaller (about 10%) and darker than the European ones. Bad news is that it’s still necessary to use morphometric analysis to differentiate them properly, especially when African genes are more diluted.

To the left, Apis mellifera scutellata or African honeybee; to the right, Apis mellifera mellifera or one of the European subspecies of honeybees. Author: Scott Bauer, USDA Agricultural Research Service, United States. Public domain.

Behaviour

African honeybees show some behavioural traits that make them potentially more dangerous than their European relatives:

1. They are more aggressive. It’s suggested that being exposed to different environmental pressures in their native habitats could be the main cause of the difference of aggressiveness between these honeybee subspecies: traditionally in Europe, beekeepers have selected less aggressive and manageable varieties, while in Africa it’s more usual to collect wild honeycombs (a practice colloquially known as ‘honey hunting’). Both ‘honey hunting’ and a major presence of natural enemies could have been lead to the selection of African varieties’ heightened defensiveness compared to that of European subspecies.

2. They accomplish massive attacks. Unlike European honeybees, which attack in groups of 10-20 individuals, African honeybees can do it in groups of 100-1000 individuals. There exist evidences of the emission of pheromones that would incite other bees to massively join the attack. Moreover, the defended area around the nest is greater and the level of stimulus needed to trigger an attack is lower than in the European honeybees.

Massive attacks accomplished by African and Africanised bees are infrequent, but stunning. In the image above, the farmer Lamar LaCaze was attacked by a swarm of 70.000 Africanised honeybees that had made their home in an old water heater (Source: Inside Edition). In the image below, the case of the climber Robert Mackley, who was attacked during about 3 hours while performing an ascension in Arizona; he was stung an estimated 1500 times (Source: Phoenix New Times; author of the picture:: Robert Mackley).

3. They swarm frequently. Honeybee colonies usually swarm 1 to 3 times a year (i.e. when the colony gets too large and resources are abundant, a new queen is reared and the hive splits), while African honeybee hives could split up to 10 times a year, even more if they feel threatened.

Swarm of African honeybees. Author: Michael K. O’Malley, University of Florida.

4. Selection of nesting site. Because African honey bees swarm more often, fewer individuals are involved in each swarm, so they do not require a large cavity to build a nest. They are also less selective than their European relatives, so they can be found inside pipes, trash cans, building cracks, holes in the ground, etc.

A colony of African honeybees inside a bucket. Author: Michael K. O’Malley, University of Florida.

Nest of Africanized honeybees in a building ceiling. Author: Ktr101, CC.

5. Nest usurpation (or colony takeover). This is probably the most curious behavioural trait of African honeybees. First of all, a small African swarm containing a queen lands on a European colony. As time passes, the worker bees in the African swarm begin to exchange food and pheromones with the European workers from the colony. This gradually ensures the adoption of the African bees into the European colony. Somewhere during this process, the European queen disappears (probably killed by the African bees) and the African queen is introduced into the colony. By this process, European bees are eventually substituted by African bees and their hybrid descendants.

Biology

Even though reproductive biology and development are very similar among honeybee races, African honeybees show some biological traits that lend them adaptive advantages with respect the European ones:

1. Greater production of drones (male bees) by parthenogenesis. African colonies produce proportionally more male bees than European honeybees, which gather during the nuptial flight forming cloud of hundreds of individuals. So, the probability that a European queen mates with an African drone increases, and thus the probability to perpetuate African genes.

2. Fast development. African colonies grow and spread faster than the European ones.

3. Greater resistance to pathogens and parasites. For example, to Varroa destructor, to the small hive beetle Aethina tumida or even to bacteria of the genus Paenabacilis, which have finished with a lot of European honeybee populations in America.

Varroa destructor on a bee nymph. Author: Gilles San Martin, CC.

The way all these traits express on hybrid bees varies depending on the proportion of African and European genes they present, which depends at the same time on the distance to the original spreading focus. So, the hybrid bees from the USA tend to be genetically closer to European honeybees and thus are less aggressive than the Africanised honeybees from other parts of America.

Are they a public health concern?

The number of stings received by their victims (causing anaphylactic reactions even in non-allergic people), the aggressiveness of their attacks, their versatility to select a nesting site (favouring their presence in urban areas) and their sensibility against any vibration or noise, are reasons enough to consider both African and Africanised honeybees a public health concern.

However, the most stunning cases of massive attacks are not as frequent as we could think. So, the real concern falls to risk groups (such as children, elderly, sick or disabled people) and to domestic animals, which would have more difficult to scape an attack.

Despite the potential risk they pose, the situation is currently well managed because a great number of exhaustive studies have allowed to carry out different measures to control their populations (and even to take advantage of them). For many years, beekeepers have been breeding African and Africanised bees to produce honey and pollinize crops in Centre and South America, becoming one of the most important honey producers worldwide. To that effect, they apply special management measures, such as letting only one colony to develop inside the hive.

Installing alert signs minimizes the risk that people come in contact with colonies of bees. Along with the premature detection of individuals and the elimination of potential nesting sites, this action is a part of the set of preventive measures to prevent the progression of their populations and the interaction of people with these organisms. Source of the picture: ALTHEA PETERSON/Tulsa World.

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Despite ‘killer bees’ could be dangerous depending on the situation, they must not be considered a great concern due to the great amount of information there exists about their populations and also about measures to control them. However, this case serves as an example of how the impact of humans on ecosystems and the introduction of foreign species can play a dirty trick on native habitats…

REFERENCES

• Calderón, R. A., Van Veen, J. W., Sommeijer, M. J., & Sanchez, L. A. (2010). Reproductive biology of Varroa destructor in Africanized honey bees (Apis mellifera). Experimental and Applied Acarology, 50(4): 281-297.
• Ellis J., Ellis A. (2012). Apis mellifera scutellata Lepeletier (Insecta: Hymenoptera: Apidae). Entomology and Nematology Department, University of Florida, USA [en linia].
• Evans, H. E. (1985). “Killer” Bees, The Pleasures of Entomology: Portraits of Insects and the People Who Study Them. Smithsonian Institution, Washington D.C. Pp 83-91.
• Ferreira Jr, R. S., Almeida, R. A. M. D. B., Barraviera, S. R. C. S., & Barraviera, B. (2012). Historical perspective and human consequences of Africanized bee stings in the Americas. Journal of Toxicology and Environmental Health, Part B, 15(2): 97-108.
• França, F. O. S., Benvenuti, L. A., Fan, H. W., Dos Santos, D. R., Hain, S. H., Picchi-Martins, F. R., Cardoso J. L., Kamiguti A. S., Theakston, R. D. & Warrell, D. A. (1994). Severe and fatal mass attacks by ‘killer’bees (Africanized honey bees—Apis mellifera scutellata) in Brazil: clinicopathological studies with measurement of serum venom concentrations. QJM, 87(5): 269-282.
• Neumann, P., & Härtel, S. (2004). Removal of small hive beetle (Aethina tumida) eggs and larvae by African honeybee colonies (Apis mellifera scutellata). Apidologie, 35(1): 31-36.
• O’Malley, M.K., Ellis, J. D., Zettel Nalen, C. M. & Herrera P. (2013). Differences Between European and African Honey Bees. EDIS.
• Winston, ML. (1992). Killer Bees: The Africanized honey bee in the Americas. Harvard University Press, Cambridge, Massachutes, USA. 176 pp.

Main photo property of Gustavo Mazzarollo (c)/Alamy Stock Photo.