Giants of the Past

Arthropleura

Reconstruction of Arthropleura amata by Jordan and Meyer*

The maximum size of arthropods has increased and decreased in the distant past in response to changing composition of earth’s atmosphere. 300 million years ago, the oxygen concentration in earth’s atmosphere may have been greater than 30% (compared to about 21% today). The higher level of oxygen allowed arthropods to attain a much larger size. When the oxygen concentration dropped, these giant went extinct.

One large species of terrestrial arthropod was Arthropleura, a centipede like creature that measured 6 feet in length and around a foot in width. This creature had one pair of legs per segment like modern centipedes. Material in the gut of Arthropleura fossils indicates that it consumed lycopods and other plants like modern millipedes.  Arthropleura is considered to be a myriapod since every segment has a pair of appendages. However, its legs have more segments than extant centipedes and millipedes so it is placed in its own taxonomic group.

The evolution and extinction of Arthropleura is linked to changes in atmospheric gas concentrations. What new species might evolve and what extant species might go extinct due to anthropogenic changes to earth’s atmosphere?

W. D. IAN ROLE and J. K. INGHAM.  Limb structure, affinity and diet of the Carboniferous  ‘centipede’ Arthropleura.  Scott. J. Geol. 3 (1), 118-124, 1967.

Posted in by jjneal, Environment, Taxonomy | 2 Comments

Living With Insects In the Home

A wide range of arthropod species will invade western style homes generating many complaints from homeowners and fueling a lucrative pest control industry. A group of scientists documented the arthropod species found in North Carolina homes and found a range of 32- 211 species per house. Not surprising, the species were dominated by Diptera (flies), spiders beetles, bees wasps and ants. Together, these account for 3/4 of the species. These arthropod groups have the greatest number of species and are well represented in overall numbers. Under represented are Lepidoptera, which comprise only 2% of the species in homes but about 15 percent of arthropod species. Cockroaches are a small fraction of the arthropod species and the number of species frequently found indoors in the US is less than a dozen species, yet the contribute 2 percent of the total. Altogether, the highly visible species should not surprise too many homeowners, but the more critic often escape detection.

Indoor Arthropods

Indoor Arthropods
From: DOI: 10.7717/peerj.1582/fig-5

Bertone MA, Leong M, Bayless KM, Malow TLF, Dunn RR, Trautwein MD. (2016) Arthropods of the great indoors: characterizing diversity inside urban and suburban homes. PeerJ 4:e1582 https://doi.org/10.7717/peerj.1582

Posted in by jjneal, Environment, Taxonomy | 1 Comment

Centipede Defense Against Microbes

House Centipede

House Centipede

Centipedes live and hunt in decaying organic matter, a substrate teeming with bacteria, fungi and other potentially harmful microorganisms. The Brazilian centipede, Scolopendra viridicornis is known to have medicinal properties. The centipedes are dried and the powder used for a variety of treatments.

Chaparro and da Silva* investigated Scolopendra viridicornis extracts and identified a novel peptide, lacrain. Interesting properties include antibiotic activity against gram negative bacteria only. Lacrain had no effect on human erythrocytes making it a candidate or lead chemical for medical uses as a bactericide. Centipedes are an under explored group that may yield new biomaterials of economic and medical importance.

* E. Chaparro & P.I. da Silva Junior. Lacrain: the first antimicrobial peptide from the body extract of the Brazilian centipede Scolopendra viridicornis. International Journal of Antimicrobial Agents.
http://dx.doi.org/10.1016/j.ijantimicag.2016.05.015

Posted in Biomaterials, by jjneal, Environment | 1 Comment

Strange Political Bedfellows

Bed Bug

Underside of Immature Bed Bug

In the down and dirty of American politics, if you don’t like a politician, you can sue them. Our media promote such stories to generate ad revenue by getting clicks from readers who are bored by policy. Hillary Clinton is being sued by opposition research groups over her actions as Secretary of State. Donald J Trump is being sued by people who paid fees to Trump University. Now one of Donald Trump’s properties, Trump National Doral Miami, is being sued by a customer, a Mr. Eric Linder, who is asking for $15,000 claiming bed bug bites that left welts, lumps, spots on his face, neck, and arm.

Many people file lawsuits. Many fewer are awarded damages. Bed bugs are commonplace in all hotels, even the five star variety. Most hotels have a bedbug inspection and management process for the protection of their customers. This gives them some protection from lawsuits based on negligent management. The problem for hotels is customers with baggage containing bedbugs. An infestation can be created overnight from an unwary customer. Most complaints are settled out of court. However, in cases of negligence, damages can be awarded. One of the highest awards was for $100,000 by a woman who stayed at a Red Roof Inn in D.C. Good hotels will give you a new room and often a refund if you find bedbugs in one their rooms.

It is not unusual for any hotel on occasion to get bedbugs and have pest control remove them.  It is not uncommon for customers of five star hotels to encounter bedbugs on some of their visits.  However, it is news if the story is linked to a prominent politician.  The thirst for something new in a process as intensely reported as a presidential election can make the media, politicians and bedbugs strange bedfellows.

Posted in Bed Bugs, by jjneal, News | 1 Comment

Zika Update: Miami Beach

Mosquito

Mosquito

Zika has now spread from a section of Miami (Wynwood) to Miami beach. Five new cases of locally transmitted Zika from Miami Beach have been confirmed. The CDC has issued a travel warning for Miami Beach. The risk of transmission is low, but outcomes for pregnant women who acquire the virus can be devastating. Travel warnings can have a large negative impact on tourism.

Mosquito control in Miami Beach is more problematic than in Wynwood. Wynwood, in North Miama has low rise apartments and is sheltered from the ocean breezes. Fogging with insecticide to kill adult mosquitoes can be effective. Miami Beach has constant sea breezes that quickly disperse pesticide aerosols and make control ineffective. High rise buildings complicate spraying logistics. More reliance on repellents will be necessary, but people are not always protected and repellents are less than 100% effective. The Florida governor is asking for federal help, but Congress has yet to approve funding and seems incapable a timely response.

CDC has a website with information and links to resources for families with infants affected by Zika. Some Zika effects are noticeable at birth, but others may develop with time. As of August 11, 2016, 529 pregnant women in US states and DC have been diagnosed with Zika, mostly travel related cases. 691 have been diagnosed in US territories, predominantly Puerto Rico. It is predicted that as much as 25% of the Puerto Rican population may become infected with Zika. Controlling Zika in Puerto Rica, with many travelers to the mainland US should have been a priority for preventing Zika in the US mainland. However, Congress is not heeding the recommendations of scientists and public health officials.

Posted in by jjneal, Health, News, Policy, Zika | Leave a comment

Living With Regeneration

House Centipede

House Centipede

Centipedes have one pair of legs per body segment. A typical house centipede has 15 pairs of legs. Centipede legs are thin, fragile and subject to loss in encounters with predators or other mishaps.

Centipedes groom their legs several times per day by bringing them in contact with the head. How does a centipede keep track? They groom the legs in sequence from front to back. If a leg is missing the centipede completes the grooming sequence as if the leg were still present. Perhaps this is similar reports of phantom sensations by humans who have lost limbs.

Centipede limbs are not lost forever. Centipedes can molt as adults, and can regenerate lost limbs. Often a regenerated limb is smaller or underdeveloped.

Posted in behavior, by jjneal, Environment | 1 Comment

Living With Arthropod Venom

Centipede

Centipede, Scolopendra subspinipes
Photo: Scott Stockwell

Many people receive bites and stings from venomous arthropods every year. These events are rarely lethal. Anaphylactic response to the venom is a factor in most all cases of mortality. People in the US are most afraid of spiders, particularly the Black Widow and Brown Recluse. Between 6-7 people per year die from spider bites in the US every year. Bees and wasps pose a greater risk:  Between 50 and 60 people die from bee and wasp stings.

Centipedes can deliver a painful bite with their first pair of legs, but mortality is seldom reported. Encounters with centipedes often end with the centipede scurrying away as fast as it can. Centipedes do not defend territory. They are mobile predators and their primary defense is escape. Thus people are unlikely to be injected with the venom of a centipede. People who are envenomated by centipedes typically have local swelling in the area of the bite. It is rare for centipede venoms to produce systemic effects.

Posted in behavior, by jjneal, Environment, Health | 1 Comment