A Feathery Facade

It may be hard to believe when you first look at it, but this is not a hummingbird. This is a hummingbird hawk-moth (Macroglossum stellatarum) from the Old World. It comes from the family Sphingidae, which contains the hawk moths, also called sphinx moths or hornworms. Unlike many moth species, this little one likes to be out during the day. Their hummingbird disguises are so superb that they even have tiny tails with markings on them and hold their legs against their bodies to make it appear as if they only have two. This is an excellent example of convergent evolution, in which unrelated species independently develop the same design or biological traits and fill the same niche.

Hummingbird hawk-moths feed on nectar like most other moths. Some other their favorite plants include butterfly bush, honeysuckle, foxgloves, and delphiniums. Just like hummingbirds, they hover by beating their wings with blinding speed and fly with extreme precision. The moth somehow knows not to visit the same flower twice in a row, as this would be an unnecessary expenditure of energy for nothing in return. How they keep track of which flowers they have gone to and which they have not isn’t currently known. Flying like they do takes so much energy that they must spend almost every minute feeding to replenish what they burn. Even while mating, the female moth may continue to feed.

Although it looks so bird-like in the air, the hummingbird hawk-moth looks very much like the moth that it is when perched.

The larvae, of course, are even less bird-like. It’s remarkable that this large grub turns into such a dainty and elegant little moth.

Hummingbird hawk-moths have relatively good vision and are able to recognize different colors quite well. Perhaps this is one of the ways they visit the individual flowers of a plant only once. They also have good navigation as they have been found to visit the same flower patches daily, similar to bees. Hummingbird hawk-moths like to fly most in bright sun, but they will also feed at dawn, dusk, and occasionally while it is raining.
So next time if you are somewhere in Southern Europe, Asia, or North Africa, find some flowers and watch them to see if you can get a glimpse of this beautiful little moth.


References:
1. Jacinto, Valtar. “Macroglossum stellatarum” Encyclopedia of Life. Eol.org, n.d. Web. 25 June 2015. < http://eol.org/pages/396579/overview&gt;

2. Kelber, A. L. M. U. T. “Colour learning in the hawkmoth Macroglossum stellatarum.” The Journal of experimental biology 199.5 (1996): 1127-1131.

3. Kelber, Almut, and U. Henique. “Trichromatic colour vision in the hummingbird hawkmoth, Macroglossum stellatarum L.” Journal of Comparative Physiology A 184.5 (1999): 535-541.

Photo and Video Links:
1. http://cdn1.arkive.org/media/67/671D969C-EBD1-4A19-B7A7-32476CC56CAC/Presentation.Large/Hummingbird-hawkmoth-feeding-side-profile.jpg

2. http://www.jochemnet.de/fiu/BSC1011/BSC1011_2/sld007.htm

3. https://www.youtube.com/watch?v=87EPaLYVA88

4. http://www.azoresbioportal.angra.uac.pt/imagens/Imagenes/Novembro19//Macroglossum_stellatarum__a3.jpg

5. http://cdn2.arkive.org/media/B9/B93184FB-54D7-43EF-BCCF-A68653658C2D/Presentation.Large/Hummingbird-hawkmoth-caterpillar-dark-morph.jpg

6. https://upload.wikimedia.org/wikipedia/commons/1/19/IC_Macroglossum_stellatarum1_NR.jpg

The Real Life ‘Alien’ – Cotesia congregata

I’m sure, even if you haven’t seen them, most of you are at least somewhat familiar with the movies in the Alien franchise and the premise behind them. You’re probably extremely grateful that there aren’t any terrifying creatures like xenomorphs stalking the earth, right? Well, that’s not entirely true. For tobacco hornworms (Manduca sexta), the caterpillars of a species of sphinx moth throughout the Americas, the horrifying scenario of Alien is a regular occurrence. This is thanks to a tiny parasitoid wasp called Cotesia congregata in the braconid family. Parasitoids are different from parasites in that they depend on the host for survival and keep it alive until they no longer have a use for it. At this point, they move on to a different stage of life, destroying the host in the process.

When it comes time to reproduce, the female wasp seeks out a larval tobacco hornworm and lays her eggs inside the body of the unfortunate caterpillar. With the eggs, she deposits a special symbiotic polyDNAvirus as well. This virus lives and multiplies exclusively inside the wasp’s reproductive system and is like a part of the wasp itself. The virus can’t reproduce on its own because it doesn’t possess the necessary genes to replicate. Instead, the genetic codes for the virus are present in the wasp’s genome. When this virus enters the caterpillar along with the eggs, it infects the caterpillar’s cells and dismantles its immune system. This protects the wasp eggs from being encapsulated and killed by the caterpillar’s hemocytes (insect blood cells). In addition to immune suppression, the virus arrests the development of the host and prevents metamorphosis into a moth. It also causes the accumulation of certain proteins in the host’s nervous system that allow it to survive for longer periods of time without food or water and alters its metabolism. This serves to keep the host alive to protect the developing wasps until they move onto their next life stage.

Credit: Doug Smith, bugguide.net

While inside the tobacco hornworm caterpillar, the C. congregata larvae hatch from their eggs and feed on the host while they grow larger and larger. By the time they are old enough to move on, the larvae have essentially eaten the host from the inside and chew their way out of its body to spin cocoons so they can pupate into adults. The larvae don’t travel away from the caterpillar at all to do this and create their cocoons right there on its body. After they pupate, the wasps emerge as fully formed adults and take to the air in search of mates in order to start the gruesome cycle all over again.

As terrible as it is for the hosts, C. congregata and many other species of parasitoid wasps are used as a means of biological control for a myriad of Lepidopterans (butterflies and moths) and other insects. There are many different species of parasitoid wasps and each of them primarily parasitizes a specific host insect. Many hosts are considered agricultural pests and wasps can be purchased and released to do their horrifying work without the destructive effects of pesticides or other artificial pest control techniques. Still, not all the insects that parasitoid wasps prey upon become hosts. The majority of them get to develop into their adult stage like our intriguing friend, the tobacco hornworm.

References:
1. Shaw, M. R., and T. Huddleston. “Classification and biology of braconid wasps.” Handbooks for the identification of British insects 7.11 (1991): 126.

2. Beckage, Nancy E., et al. “Characterization and biological effects of Cotesia congregata polydnavirus on host larvae of the tobacco hornworm, Manduca sexta.” Archives of Insect Biochemistry and Physiology 26.2‐3 (1994): 165-195.

3. Beckage, Nancy E., and Michael R. Kanost. “Effects of parasitism by the braconid wasp Cotesia congregata on host hemolymph proteins of the tobacco hornworm, Manduca sexta.” Insect biochemistry and molecular biology 23.5 (1993): 643-653.

4. Beckage, Nancy E., and Dale B. Gelman. “WASP PARASITOID DISRUPTION OF HOST DEVELOPMENT: Implications for New Biologically Based Strategies for Insect Control*.” Annual Reviews in Entomology 49.1 (2004): 299-330.

Photo Links:
1. http://www.mdpi.com/insects/insects-03-00091/article_deploy/html/images/insects-03-00091-g001-1024.png

2. http://bugguide.net/images/cache/FH2/HZR/FH2HZRPHOHML6ZRLEZ5L9Z8LEZ8LRREHBZXLBZ2HFHXLVZ6HYHNH3H6H3HXH5ZRL8ZRL6Z0L6ZKLEZGHVH8H1HLL.jpg

3. https://upload.wikimedia.org/wikipedia/en/c/c0/Caterpillar_with_eggs3.jpg

4. http://www.nsf.gov/news/mmg/media/images/Manduca_sexta13b_h.jpg

Spectral Leaf – Ghost Mantis

Yes, it’s another mantis, but they’re really cool insects, so why not?

The Ghost mantis (Phyllocrania paradoxa) is a tiny mantis found throughout Eastern and Western Africa and occasionally in the South, including the island of Madagascar. It mainly lives in drier areas and clings to the leaves and twigs of different plants in its habitat. It only grows up to about two inches in length and is considered to be miniature for a mantis. Ghost mantis males and females are roughly the same length, but the male is slimmer and has slightly longer wing cases that are partially transparent. Males also have eight abdominal segments, whereas females possess only 6. They can be a variety of different colors ranging from a subtle brownish green to almost black. The most common color is dark brown, however.

Two females next to a  50 euro coin:

Like the orchid mantis, ghost mantises boast some of the most impressive camouflage of the insect world. The thorax is slightly flattened into a leaf-like shape and each of the walking legs and abdomen have projections that mimic dead leaves as well. A ghost mantis’ back is laced with thin veins and mottled with pigmentation that mimics leaf folds. The head is probably the weirdest and most intriguing part of the animal’s body. Its eyes are almost invisible due the fact that they are the exact color as the rest of its exoskeleton. Above them is a long, ghoulish crest that resembles a dried and withered leaf. In addition to the ghost mantis’ physical camouflage, it also displays behavioral camouflage. It will often tuck its forelegs up tight against its body to give it an unusual shape that may confuse potential predators. When disturbed, it will start to rock back and forth to mimic a leaf blowing in a gentle breeze.

Ghost mantises aren’t typically very active. They mainly hang upside down on leaves and branches while waiting for prey. They possess no attributes that help lure other creatures to them, so their only hunting strategy is to hide and stay still. Crawling insects are the most common prey items as they have more trouble taking down flying insects. A ghost mantis can stay motionless in the same spot for hours ready to seize prey that comes too near. It may quickly turn its head to look at something it sees, but the rest of its body remains unmoving. If something comes by that is a threat rather than food, the first line of defense will be to get away or use that quaking motion described earlier. If that fails, it uses thanatosis (plays dead) to try to fool whatever is startling it. It does this by folding all of its legs into its body and dropping to the ground. This may seem like it would make the mantis an easy target, but most of its predators are only interested in live prey so it actually works quite well.

Similar to many other species of mantis, ghost mantis babies are disguised as ants to avoid being eaten. Many mantis predators such as spiders and large insects avoid ants because they can be so dangerous. A baby ghost mantis is just the right size for this gimmick to work before the second molt, but after that it becomes too big to pull it off and begins to take on the appearance of an adult. Although the ghost mantis is slightly longer lived than other mantises, its life is still short. Even so, it’s very special that such a cool animal like this exists.

References:
1. Tomasinelli, Francesco, and Andrea Mangoni. “Biology and Captive Breeding of the African Dead Leaf Mantis Phyllocrania Paradoxa.” Mantis Study Group Newsletter 23 (Feb. 2002): 1-12. http://mantodea.myspecies.info/sites/mantodea.myspecies.info/files/MSG%20NL%2023%20%28February%202002%29.pdf

2. “Ghost Mantis – Phyllocrania paradoxa.” Keeping Insects. Keepinginsects.com, n.d. Web. 23 June2015. http://www.keepinginsects.com/praying-mantis/species/phyllocrania-paradoxa/

Photo Links:
1. https://upload.wikimedia.org/wikipedia/commons/c/c8/Phyllocrania_paradoxa_Morphology.jpg

2. http://www.pxleyes.com/blog/wp-content/uploads/camouflage-photography-in-the-animal-world-50-astonishing-photos/29.jpg

3. https://upload.wikimedia.org/wikipedia/commons/thumb/2/2d/Phyllocrania_Paradoxa_F_Subadult.jpg/640px-Phyllocrania_Paradoxa_F_Subadult.jpg

A Deceptive Flower – Malaysian Orchid Mantis

The Malaysian orchid mantis (Hymenopus coronatus) is a unique species of mantis that lives in the South Asian rainforests of Malaysia, Sumatra, and Indonesia. It is quite small, only about two and a half inches long at most for the female, and displays the greatest sexual dimorphism of all the mantids. Males are half the size of the female and there is even a slight difference in the coloring of a band-like marking around the neck. This marking is green in sub-adult females and a brownish purple on sub-adult males. Either color goes nicely with the subtle, creamy pastel shades of the mantis’ body. The species itself can come in a range of colors depending on what environment it matures in. Most often it is white or pink, but there can be purple, yellow, green and a variety of other colors.

Adult male and female:

Although the Malaysian orchid mantis is a beautiful creature, it is also a vicious predator. As the name suggests, this mantis often chooses orchid flowers as its hunting grounds. Its body is camouflaged perfectly to match the botanical backdrop on which it hides. The four walking legs are even equipped with petal mimicking projections so as to camouflage better. All the mantis needs to do is lie in wait, perfectly still, for some poor unsuspecting insect to visit the flower. Once this occurs, the mantis grabs it up in its sharp, spiny forelegs with lightning speed and proceeds to rip it apart with its powerful jaws. It uses this same weaponry to defend itself from harm when threatened and can become quite aggressive if disturbed. First it will rise up into a threat display with its arms outstretched and wings spread wide. If it still feels bothered then it will attack. Those arms can actually inflict a good amount of damage to a human hand and the mantis will not hesitate to bite any place it can reach.

Another very interesting defense is used only by orchid mantises when they are very young nymphs. The little baby mantises walk around disguised as a dangerous species of ant. They hold their abdomens curled over their bodies and move with an ant-like motion. They walk on all six legs, which are tipped in black, contrasting with their bright red bodies. This allows them to avoid predators that aren’t looking to mess around with getting stung or bitten by ants and also as a cover-up to go hunting real ants. It is evident that these clever insects are masters of camouflage at every stage of life.

Ant mimicking nymph:

Although the ant disguise is a striking technique, it doesn’t last long. A nymph loses this costume after the first molt and begins to look like a tiny adult instead. Orchid mantis females go through seven molts to reach adulthood and males go through five, maturing much quicker but living shorter lives. The average female lives about eight months while a male will only live to be five or six months old. Once a nymph becomes an adult, it develops large wings and becomes a very good flier and can travel more effectively. Orchid mantises don’t just frequent orchids. They will hang around in many other flowering plants and trees such as papayas and the wonderfully scented plumeria. So if you live in Southern Asia, definitely go check out some flowers to see if you can find one of these stunning insect beauties.

Sub-adult female:

References:
1.”Orchid Mantis – Hymenopus Coronatus.” Keeping Insects. Keepinginsects.com, n.d. Web. 23 June 2015. <http%3A%2F%2Fwww.keepinginsects.com%2Fpraying-mantis%2Fspecies%2Forchid-mantis%2F>.

2. O’hanlon, J. C., D. Li, and Y. Norma-Rashid. “Coloration and morphology of the orchid mantis Hymenopus coronatus (Mantodea: Hymenopodidae).” Journal of Orthoptera Research 22.1 (2013): 35-44.

3. “Malaysian Orchid Mantis.” WAZA. World Association of Zoos and Aquariums, n.d. Web. 23 June 2015. <http%3A%2F%2Fwww.waza.org%2Fen%2Fzoo%2Fchoose-a-species%2Finvertebrates%2Finsects-and-millipedes%2Fhymenopus-coronatus>.

Photo Links:
1. http://lemondedesphasmes.free.fr/IMG/jpg/Hymenopuscoronatuscoupleadulte2.jpg

2.http://i.dailymail.co.uk/i/pix/2015/01/27/251D8E8800000578-0-image-a-43_1422365247535.jpg

3. https://s-media-cache-ak0.pinimg.com/736x/c1/d7/77/c1d777466221bdcf3f8634826ec41996.jpg

4. http://i0.wp.com/blog.safariltd.com/wp-content/uploads/2014/10/Pink-Praying-Mantis.jpg

Gifts of Love – The Dance Fly

When a person says dance fly, most people would likely think of a dancing housefly. However, there is actually such an insect that goes by this name, though it is very different from the common housefly. Dance flies, also called balloon flies or dagger flies, are predatory Dipterans that are members of the family Empididae. Empids are characterized by their long, pointy mouth parts and their extravagant mating rituals. If a fly can be charming, dance flies are certainly the ones that fit the bill. During the mating time, swarms of male dance flies will gather together and perform for nearby females while carrying delicate, specially crafted silk balloons. These balloons are called nuptial gifts and a successful male will pass his balloon to his partner during mating and they will often tumble to the ground together.


Credit: Mark Shields

Nuptial gifts in the form of silk balloons are unique to this family. Often, these balloons will contain a protein rich meal for the female to consume whilst mating. Typically, the larger the prey item, the more time the male gets to mate and the more sperm he can deliver. Other insects such as scorpionflies show this behavior as well, but they do not construct balloons to carry the prey items as dance flies do.


Credit: Allen B. Coovert

Jennifer Sadowski and her team (1998) have shown that an interesting phenomenon has evolved in certain species of dance flies, more specifically, Empis snoddyi. What they’ve learned is that males of this species no longer offer prey to their female mates, but just the silken balloon, which has no nutritional value and serves no purpose for the female other than to hold during copulation. This is called an “empty” nuptial gift. Although females will accept gifts of no direct or indirect benefit to themselves, they can still be choosy about who they take as their partners. This study found that there is an inverse correlation between balloon size and body size within successful males. It appears that female choice over generations has selected for a smaller balloon size and bigger male body size. Sadowski et al. noticed that the most successful males weren’t necessarily the ones with the smallest balloons, though. They observed that males with large body sizes and intermediate sized balloons took the most mates. There are a number of reasons why this may be. When sexual selection favors female choice, there are often signs that females look for in a mate that are indicative of their health and good genetics. In dance flies, females will chase their chosen male out of the swarm before deciding to mate with him. This could possibly be an assessment of his flying ability and fitness. It makes sense, then, that males with larger balloons would have a more difficult time performing at the top of their game. The bigger a balloon is, the more cumbersome it might be and could hinder a male’s flight displays. On the other end of the spectrum, a female requires a gift to mate and if a balloon is so small that it is not readily visible to her, she may ignore the male carrying it. As we can see from these animals, the courtship and mating process of insects can be complex, elaborate, and elegant. It isn’t just the more charismatic animals like mammals that can show fascinating sexual behavior. Next time you go outside and notice the insects around you, consider the intricacies of their intimate behaviors and marvel at the great variation of life on this planet.


Credit: Lexi Menth (Me)

References:
1. Sadowski, Jennifer A., Allen J. Moore, and Edmund D. Brodie III. “The evolution of empty nuptial gifts in a dance fly, Empis snoddyi (Diptera: Empididae): bigger isn’t always better.” Behavioral ecology and sociobiology 45.3-4 (1999): 161-166.

2. Cumming, Jeffery M. “Sexual selection and the evolution of dance fly mating systems (Diptera: Empididae; Empidinae).” The Canadian Entomologist 126.03 (1994): 907-920.

Photo Links:
1.http://bugguide.net/images/cache/PZK/LGZ/PZKLGZSL9ZGHJHPHYH9HYH2HBHZLNZILWZ7L3HMLAZMLFHWHJH9HYH5LAZ2HNZMLRREHFHIL3H6HJHNHBZ8L9Z4LFH.jpg

2. https://i2.wp.com/i.guim.co.uk/static/w-620/h–/q-95/sys-images/Observer/Pix/pictures/2014/8/28/1409245016782/Empis-vockerothi-008.jpg

3.https://i1.wp.com/bugguide.net/images/cache/IZT/L0Z/IZTL0ZDL3L0HQRDZKRLH4RQHERKHERYZZZ3ZYLULLZTLKZBL5RZHSZLH6R0HGRLH2RZHKZQHIRELYL3Z7R9LMRQHPRZH.jpg