Euoniticellus intermedius

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Euoniticellus intermedius
CSIRO ScienceImage 271 Euoniticellus intermedius Dung Beetle.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Scarabaeidae
Genus: Euoniticellus
Species:
E. intermedius
Binomial name
Euoniticellus intermedius
(Reiche, 1849)

Euoniticellus intermedius (also known as the Northern Sandy Dung Beetle) is a species of dung beetle in the family Scarabaeidae. [1] [2] E. intermedius is native to Southeastern Africa but has spread to the United States, Mexico, and Australia. [3] E. intermedius acts as an important agricultural agent due to its improvement of soil quality and removal of parasitic pests. [3]

Contents

Adults of the species are brown in color and exhibit sexual dimorphism. Males can be identifying by their blunt, curved horns, which are used to fight with other males for female mates. [4]

These beetles spend their entire lives in dung pads. They are of the tunneling variety of dung beetles, which bring dung into their tunnels as opposed to living in the dung or rolling the dung away. [5]

Description

Adults are generally 6mm to 10mm long. Younger adults tend to be light brown or tan in color, though their thoraxes are darker. Older adults tend to be a darker brown and more uniformly colored. The brown coloring of adults and the adherence of dried dung to their shells allows adult beetles to camouflage into their surroundings. [4]

E. intermedius exhibits sexual dimorphism, with males possessing blunt, curved horns that females do not. Males also possess thinner, curvier fore tibia and more swollen anterior dorsal portions as compared to females. [4]

Geographic range

E. intermedius originates from the Afrotropical realm with distribution ranging from Ethiopia to South Africa. It has since spread into other geographical regions both intentionally and unintentionally. [6]

These beetles were introduced to Australia from South Africa in 1971 for agricultural purposes. They are now in all of Australia's mainland states except for Victoria. [3]

This species was then introduced to the United States for similar agricultural reasons. E. intermedius was first released into Hawaii from Australia in 1974. This species was then brought to California, Texas, and Georgia in the 1970s and 1980s. [3] It has also been found in Florida, but distribution patterns in the rest of the United States remain unclear. [6]

E. intermedius has also spread throughout most of Mexico from its northern border with the United States to its southern border with Guatemala. Despite not having been released in Mexico, these beetles have been identified in 15 of the 32 Mexican states. [3]

Habitat

These beetles are generally distributed throughout the entirety of the geographical regions in which they are found but are more prevalent in areas associated with livestock or pastures. Their successful spread has been attributed to their high fecundity, adaptability, and vagility. [7]

E. intermedius is highly tolerant of hot, arid conditions. Though attracted to fresher dung, these beetles are able to undergo their entire life cycle using dry feces under drought conditions. These beetles are able to produce high brood numbers under the wilting point but can also resorb ovarian oocytes under stressful conditions. E. intermedius are able to survive in a broader thermal window than other dung beetle species. They are also highly resistant to agrochemicals and active during the afternoon when most dung beetle species are dormant. [3]

E. intermedius's high tolerance for extreme conditions and avoidance of competition with other dung beetle species have allowed it to act as a successful invader and spread to regions with a variety of climates. [3]

Food resources

E. intermedius feed on dung similarly to other dung beetle species. This species exhibits a strong preference for cow dung and dung that is no older than 36 hours. [4] The adults primarily feed on the nutritionally rich particulate portion of the dung. The larvae differ in that they consume coarser, fibrous portions of the dung. [8]

Larvae and adults possess differing anatomical adaptations that support their differing diets. Larvae have a compartmentalized hindgut, which likely contains symbiotic bacteria that help digest the cellulose in plant fibers. This anatomical feature disappears in adult beetles. Larvae also have ancestral, sclerotized mandibles that allow them to consume tougher portions of the dung, while adults have specialized, soft mandibles that facilitate the consumption of softer dung. [8]

Life history

As beetles, E. intermedius undergoes complete metamorphosis with egg, larval, pupal, and adult states. Adults take around six weeks to develop from eggs and live for approximately two months afterward. [5] Studies have found that temperature poses a strong effect on their life cycle. Cooler temperatures slow down the timeline of their life cycle up to the point of halting development. Warmer temperatures shortened the beetles’ lifespan and led to greater egg production. [5]

Egg

Eggs are 2mm egg that is bean-like in shape and pearly-white in color. Eggs are laid within the egg chambers of their own individual brood balls. [4] The eggs take approximately one week to hatch into larvae. [5]

Larva

Larvae of E. intermedius appear similar to those of other dung beetle species, with a dorsal expansion and caudal flattening that help the larvae move within the brood ball. Larvae undergo three instars over the course of a week, growing from 2.5mm to 8mm over the course of all three instars. First-instar larvae have soft, round, milky-white head capsules. Second-instar and third-instar larvae are anatomically identical to first-instar larvae aside from having light-yellow and straw-colored head capsules. [9] Larvae begin feeding during the second instar and create a pupation chamber out of their own excrement at the end of the third instar. [5]

Pupa

The pupa of E. intermedius lasts for approximately two weeks, with pupae being around 10mm in length. [5] Their pupa are white and morphologically quite different from third-instar larvae. [10] Pupae possess a calluslike pronotal support projection and fingerlike lateral and dorsal tergal support projections along with calluslike caudal projections sometimes. [4]

Adult

After approximately two weeks as pupae (six weeks total), the pupa emerge as 10mm teneral imago emerge. [5] Adult beetles then spend the majority of their time feeding on and tunneling in their dung pad as they sexually mature. [4]

Similarly to other dung beetles, E. intermedius construct dung balls from dung pads in order to create brood masses in which they can lay their eggs. E. intermedius are categorized as paracoprids, or tunnelers, meaning that they construct burrows underneath dung pads in which to store brood masses. The number of brood masses created vary based on dung quality and quantity, intraspecies and interspecies conflict, and environmental conditions, such as temperature and moisture. [4]

After achieving sexual maturity, male and female beetles construct brood masses in tunnels under dung pads collaboratively, though research studies have found that females are able to do so independently. The female beetle typically forms the brood mass while the male beetle transports mass from the dung pad to the female. [4]

E. intermedius produces brood masses consisting of a dung shell surrounding an egg chamber. E. intermedius has been found to produce egg chambers larger than other species of dung beetle. The egg chamber is lined with semiliquid dung and the egg is attached to the bottom before the egg chamber is enclosed with a fibrous aeration plug composed of dung. [4]

E. intermedius beetles lay up to 8 eggs per nest based on environmental conditions after an embryonic period of around 4–5 days, producing an average of 120 eggs over their lifetime. [3] [11] Once brood formation is complete, beetles travel to find new dung pads at which to reproduce again. [4]

Mating

Studies have shown that mating is mediated by competition between male beetles. In the absence of other male competitors, male beetles will enter tunnels dug by female beetles to mate. Otherwise, male beetles will guard their female mates and fight off male competitors by pushing them out of the tunnel with their horns. Although some male beetles would either retreat before physical conflict or reenter the tunnel after being forced out, no males are able to sneak past guarding males, which is true with other beetle species. Body size and horn size are both important predictors of male success in competitions, but horn size has been found to be increasingly important with increasing body size. [12]

Male/male interactions

The presence of horns on this species acts a secondary sexual ornament that acts as a direct indicator of a beetle's ability to win in fights against other males. Studies were conducted to correlate fighting ability with physical attributes of these beetles, taking into account features such as horn zine and body size. In competitions between males, the strength to drag their opponent out of tunnels and the endurance to withstand exhaustion were key skills that beetles must display in order to emerge victorious in fights. It was discovered that horn size and body length could be linked to these abilities. While body length is only a good predictor for the pulling force of the beetle, horn size can be used as a more accurate and reliable indicator of performance in both these areas. Body weight and horn size are positively correlated. This type of study that emphasizes an integrative approach by taking into account multiple factors when studying fighting outcomes is invaluable for understanding the evolution of these traits and behaviors. [13]

Interactions with humans and livestock

Agricultural use

E. intermedius has been intentionally introduced to ecosystems in the United States and Australia for their positive contributions to agriculture. [4]

Soil quality

Tunnelling by E. intermedius improves the soil quality through percolation and aeration. This allows for increased water infiltration, leading to increased soil moisture, decreased soil density, and reduced surface water runoff culminating in decreased soil erosion. This allows for greater soil quality on agricultural land, which promotes plant growth. Similar effects have been observed when studied in the extremely degraded soil of coal mines. [14]

Dung consumption and transportation by these beetles contributes to nutrient recycling. Incorporation of manure into the soil from the surface allows nitrogen that would otherwise have been almost entirely lost through volatilization to be used by plants. Additionally, larvae leave behind the uneaten portions of their brood balls as organic matter with which soil microbes create humus, a crucial contributor to soil health. [15]

Dung removal by E. intermedius also increases effective pasture acreage. Livestock have been shown to not graze near their own species’ manure, which is removed by these beetles. [15]

Parasite control

Dung manipulation by E. intermedius has been shown to reduce the population of parasitic pests. E. intermedius introduction has been found to significantly decrease fly larvae emergence due to competition for dung as a food source and damage to fly eggs. E. intermedius introduction has been found to decrease gastrointestinal parasites by disrupting their eggs, which are found in the feces of cattle. [5] [15]

Herbicide and drug effects

E. intermedius has been used to investigate the effects of compounds and medicines used in the agricultural industry on nontarget organisms. Studies on herbicides have found that a common herbicide mixture, consisting of 2,4-dichlorophenoxyacetic acid and picloram, to pose no negative effect on E. intermedius beetles. Rather, it has been shown that application of said herbicide mixture improved the condition and size of these beetles. [11] Studies on antiparasitic drugs have found that ivermectin injection into cattle produces ivermectin residue in cow dung, which delayed adult emergence by up to a week and decreased productivity in the first week of breeding for E. intermedius. Studies explored the survival, fecundity, and development of this species after ivermectin was introduced to cattle dung. Researchers found that adult survival was reduced to nearly 50% and eventually reached total mortality at greater concentrations. Upon closer inspection, it was noted that ivermectin didn't impact the ovary, but increased testicle size and reduced the fecundity and weight of the broods. Ivermectin increased the development time for E. intermedius which reduced their numbers. Further research involving the impact of ivermectin on E. intermedius and its surroundings are vital to understanding the implications of its use in agriculture. [9]

Related Research Articles

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Silphidae is a family of beetles that are known commonly as large carrion beetles, carrion beetles or burying beetles. There are two subfamilies: Silphinae and Nicrophorinae. Members of Nicrophorinae are sometimes known as burying beetles or sexton beetles. The number of species is relatively small, at around two hundred. They are more diverse in the temperate region although a few tropical endemics are known. Both subfamilies feed on decaying organic matter such as dead animals. The subfamilies differ in which uses parental care and which types of carcasses they prefer. Silphidae are considered to be of importance to forensic entomologists because when they are found on a decaying body they are used to help estimate a post-mortem interval.

<span class="mw-page-title-main">Dung beetle</span> Informal group of insects

Dung beetles are beetles that feed on feces. Some species of dung beetles can bury dung 250 times their own mass in one night.

<span class="mw-page-title-main">Hercules beetle</span> Species of beetle

The Hercules beetle is a species of rhinoceros beetle native to the rainforests of southern Mexico, Central America, South America, and the Lesser Antilles. It is the longest extant species of beetle in the world, and is also one of the largest flying insects in the world.

<i>Dynastes tityus</i> Species of beetle

Dynastes tityus, the eastern Hercules beetle, is a species of rhinoceros beetle native to the Eastern United States. The adult's elytra are green, gray or tan, with black markings, and the whole animal, including the male's horns, may reach 60 mm (2.4 in) in length. The larvae feed on decaying wood from various trees.

<i>Phanaeus vindex</i> Species of beetle

Phanaeus vindex, also known as a rainbow scarab, is a North American species of true dung beetle in the family Scarabaeidae. It is found in eastern and central United States and northern Mexico. It is the most widespread species of Phanaeus in the United States and it has a wide habitat tolerance. It may hybridize with the generally less common P. difformis.

<span class="mw-page-title-main">Japanese rhinoceros beetle</span> Species of beetle

Allomyrina dichotoma, also known as the Japanese rhinoceros beetle or Japanese horned beetle, is a species of rhinoceros beetle. They are commonly found in continental Asia in countries such as China, the Korean peninsula, Japan, and Taiwan. In these areas, this species of beetle is often found in broad-leaved forests with tropical or sub-tropical climates. This beetle is well known for the prominent cephalic horn found on males. Male Japanese rhinoceros beetles will use this horn to fight other males for territory and access to female mating partners. Upon contact, males will attempt to flip each other onto their backs or off of their feeding tree. In response to selective pressures, smaller male A. dichotoma have adapted a "sneak-like behavior". These smaller beetles will attempt to avoid physical confrontation with larger males and try to mate with females.

<span class="mw-page-title-main">Scarabaeinae</span> Subfamily of beetles

The scarab beetle subfamily Scarabaeinae consists of species collectively called true dung beetles. Most of the beetles of this subfamily feed exclusively on dung. However, some may feed on decomposing matter including carrion, decaying fruits and fungi. Dung beetles can be placed into three structural guilds based on their method of dung processing namely rollers (telecoprids), dwellers (endocoprids) and tunnelers (paracoprids). Dung removal and burial by dung beetles result in ecological benefits such as soil aeration and fertilization; improved nutrient cycling and uptake by plants, increase in Pasture quality, biological control of pest flies and intestinal parasites and secondary seed dispersal. Well-known members include the genera Scarabaeus and Sisyphus, and Phanaeus vindex.

Cephalodesmius is a genus of Scarabaeidae or scarab beetles.

<i>Coprophanaeus</i> Genus of beetles

Coprophanaeus is a genus in the family Scarabaeidae. The genus is almost entirely Neotropical, with a single species, C. pluto, ranging into southernmost Texas in the United States. They are medium-sized to large beetles, with the South American C. ensifer and C. lancifer sometimes exceeding 5 cm (2 in) in length, making these two some of the largest dung beetles in the world and the largest in the Americas. They often have a horn on the head, and are typically a bright metallic color, most often blue or green, or black. These diurnal or crepuscular beetles are excellent diggers and good fliers.

<i>Bolitotherus</i> Species of beetle

Bolitotherus cornutus is a North American species of darkling beetle known as the horned fungus beetle or forked fungus beetle. All of its life stages are associated with the fruiting bodies of a wood-decaying shelf fungus, commonly Ganoderma applanatum, Ganoderma tsugae, and Ganoderma lucidum.

<i>Onthophagus taurus</i> Species of beetle

Onthophagus taurus, the taurus scarab, is a species of dung beetle in the genus Onthophagus and the family Scarabaeidae. Also known as the bull-headed dung beetle, it is a species that specializes in cattle dung and is widely utilized to maintain clean pastures, making it agriculturally valuable. These beetles are typically 8–10 millimetres (0.31–0.39 in) in size. The males of this species exhibit distinct characteristics: large “major” males possess long, sweeping, curved horns resembling those of a longhorn bull, while small “minor” males have tiny horns that project upward from the back of their heads. Females, on the other hand, lack horns. These small beetles are oval shaped, the color is usually black or reddish brown. Sometimes the pronotum has a weak metallic sheen.

<i>Coprophanaeus ensifer</i> Species of beetle

Coprophanaeus ensifer is a large South American species of beetle belonging to the family Scarabaeidae. This species is necrophagous and builds burrows near or on animal carcasses to dismember the flesh of decaying bodies and bring it to its burrow to feed. Both females and males help build the burrow and feed. It is characterized by its iridescent colors and a horn that is similar in shape and size in females and males. It uses its horn to tear apart carcasses and to fight with other individuals, with male-male fighting occurring more often. However, females also fight to determine a variety of characteristics of the opposing male. This species may be of importance in forensic science due to its destructive behavior on decaying bodies, especially in areas of Brazil where homicide rates are high.

<i>Phanaeus</i> (beetle) Genus of beetles

Phanaeus, the rainbow scarabs, is a genus of true dung beetles in the family Scarabaeidae, ranging from the United States to northern Argentina, with the highest species richness in Mexico. Depending on species, they can inhabit a wide range of habitats, from tropical to temperate climates and deserts to rainforests. In those living in relatively arid places adults are primarily active during the wet season and those living in relatively cold places are primarily active during the summer. They are excellent diggers and good fliers.

<i>Maladera formosae</i> Species of beetle

Maladera formosae, commonly known as the Asiatic garden beetle and formerly known as Maladera castanea, is a species of beetle in the family Scarabaeidae. It is native to Japan, China, South Korea, North Korea, and Russia but was introduced to North America in the 1920s where it is considered a pest of turfs, gardens, and crop fields. Adults are active in the summer during which they can be found feeding on leaves and flowers or gathering around light sources at night.

<i>Sulcophanaeus imperator</i> Species of beetle

Sulcophanaeus imperator is a brightly colored species of dung beetle belonging to the family Scarabaeidae. This diurnal, coprophagous beetle is native to south-central South America and generally common. It is paracoprid, meaning that adults dig tunnels into the soil under the food source and move parts of the food source to a nest chamber where the eggs are laid.

<i>Teuchestes fossor</i> Species of beetle

Teuchestes fossor is a species of dung beetle native to the Palaearctic, but is also widespread in North America following accidental introduction and naturalisation during European settlement. Both adults and larvae are coprophagous, differentiating resource use by respectively feeding on the liquid and fibrous fractions of herbivore dung. It can be readily collected from the dung of livestock, and other large mammals This species is known to support a number of key ecosystem services in cattle pastures.

<span class="mw-page-title-main">Oniticellini</span> Tribe of beetles

Oniticellini are a tribe of scarab beetles, in the true dung beetle subfamily (Scarabaeinae). Nearly all species of this tribe feed on and nest in dung, mainly that of large herbivores. Most are tunnelers; dung is buried at the ends of tunnels dug below a dropping, and used as food by both adults and larvae; others, known as dwellers make brood cavities within or just beneath the dung.

<span class="mw-page-title-main">Sisyphini</span> Tribe of beetles

Sisyphini is a tribe of scarab beetles, in the dung beetle subfamily (Scarabaeinae), but it may now be combined with the Scarabaeini. The middle and hind legs are very long; the relatively short body is laterally compressed and has flattened sides. Relative to other dung beetles they are of small to moderate size.

<i>Liatongus rhadamistus</i> Species of beetle

Liatongus rhadamistus, or Scaptodera rhadamistus, is a species of dung beetle found in India, Sri Lanka, Laos and Thailand.

<i>Coprophanaeus lancifer</i> Species of beetle

Coprophanaeus lancifer is a large species of beetle belonging to the family Scarabaeidae.

References

  1. ↑ "Euoniticellus intermedius Report". Integrated Taxonomic Information System. Retrieved 2019-09-24.
  2. 1 2 3 4 5 6 7 8 Pokhrel, M. R.; Cairns, S. C.; Andrew, N. R. (2020). "Dung beetle species introductions: when an ecosystem service provider transforms into an invasive species". PeerJ. 8: e9872. doi: 10.7717/peerj.9872 . PMC   7531351 . PMID   33062417.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 Blume, R. R. (1984). "Euoniticellus intermedius (Coleoptera: Scarabaeidae): Description of Adults and Immatures and Biology of Adults". Oxford Academic.
  4. 1 2 3 4 5 6 7 8 Hull, R.; Alaouna, M.; Khanyile, L.; Byrne, M.; Ntwasa, M. (2013). "Lifestyle and Host Defense Mechanisms of the Dung Beetle, Euoniticellus intermedius: The Toll Signaling Pathway". Journal of Insect Science. 13 (108): 108. doi:10.1673/031.013.10801. PMC   4011371 . PMID   24735102.
  5. 1 2 Wood, L. A.; Kaufman, P. E. (2008). "Euoniticellus intermedius (Coleoptera: Scarabaeidae: Scarabaeinae: Tribe Coprini): Its Presence and Relative Abundance in Cattle Pastures in Northcentral Florida". Florida Entomologist. 91: 128. doi: 10.1653/0015-4040(2008)091[0128:EICSST]2.0.CO;2 . ISSN   0015-4040.
  6. ↑ Edmonds, W. D. (2018). "The dung beetle fauna of the Big Bend region of Texas (Coleoptera: Scarabaeidae: Scarabaeinae)". DigitalCommons@University of Nebraska - Lincoln.
  7. 1 2 Shukla, S. P.; Sanders, J. G.; Byrne, M. J.; Pierce, N. E. (2016). "Gut microbiota of dung beetles correspond to dietary specializations of adults and larvae". Molecular Ecology. 25 (24): 6092–6106. Bibcode:2016MolEc..25.6092S. doi:10.1111/mec.13901. PMID   27801992. S2CID   19130998.
  8. 1 2 Rosales, M. C.; Martinez, I.; Lopez-Collado, J.; Vargas-Mendoza, M.; Gonzalez-Hernandez, H.; Fajersson, P. (2012). "Effect of ivermectin on the survival and fecundity of Euoniticellus intermedius (Coleoptera: Scarabaeidae)". Revista de Biología Tropical. 60 (1): 333–345. PMID   22458228.
  9. ↑ Martinez, Imelda; Jean-Pierre, Lumaret; Diego, Ana; Cano, Bulmaro. "The Reproductive Biology of Euoniticellus intermedius (Reiche) (Coleoptera: Scarabaeinae: Oniticellini)". ResearchGate.
  10. 1 2 Gonzalez-Tokman, D.; Martinez-Morales, Imelda; Farrera, Arodi; Ortiz-Zayas, M. D. R.; Lumaret, J. (2017). "Effects of an herbicide on physiology, morphology, and fitness of the dung beetle Euoniticellus intermedius (Coleoptera: Scarabaeidae)". Environmental Toxicology and Chemistry. 36 (1): 96–102. doi:10.1002/etc.3498. PMID   27206992. S2CID   4330191.
  11. ↑ Pomfret, J. C.; Knell, R. J. (2006). "Sexual selection and horn allometry in the dung beetle Euoniticellus intermedius". Animal Behaviour. 71 (3): 567–576. doi:10.1016/j.anbehav.2005.05.023. S2CID   53183504.
  12. ↑ Lailvaux, S. P.; Hathway, J.; Pomfret, J.; Knell, R. J. (August 2005). "Horn size predicts physical performance in the beetle Euoniticellus intermedius (Coleoptera: Scarabaeidae)". Functional Ecology. 19 (4): 632–639. doi:10.1111/j.1365-2435.2005.01024.x. ISSN   0269-8463.
  13. ↑ Dabrowski, J.; Venter, G.; Truter, W. F.; Scholtz, C. H. (2019). "Dung beetles can tunnel into highly compacted soils from reclaimed mined sites in eMalahleni, South Africa". Applied Soil Ecology. 134: 116–119. Bibcode:2019AppSE.134..116D. doi:10.1016/j.apsoil.2018.10.015.
  14. 1 2 3 Torabian, S.; Leffler, A. J.; Perkins, L. (2024). "Importance of restoration of dung beetles in the maintenance of ecosystem services". Ecological Solutions and Evidence. 5 (1). Bibcode:2024EcoSE...5E2297T. doi: 10.1002/2688-8319.12297 .

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