Skip to main content

#49: Spider Mites


Litinsects #49:

Month of Mites, Part 5

Let me introduce you to some pesky little dudes called spider mites. There are about 1200 species of spider mites and they are huge agricultural/commercial pests. The TWO-SPOTTED SPIDER MITE shown in these photos (named for, you guessed it, its two dark spots) is one of the most well-known and economically important pests worldwide because it feeds on hundreds of plant species. I worked with these mites as part of my master’s thesis and was able to witness firsthand how they can decimate plants if left uncontrolled!
 
  • So why are they called spider mites? Because they spin silk WEBBING that can cover entire plants. The webbing serves as protection for the colony from weather, desiccation, and pesticides but also protects from predators, who can’t maneuver through it very well
     

  • Spider mite females are larger, at around 0.5 mm and males are around 0.3 mm. The eggs are round and 0.15 mm in size. Just before hatching, the mites’ RED EYES are visible inside the eggs! 
     
  • Spider mites feed by penetrating plant epidermal cells and sucking out the contents, leaving characteristic pale patches on the leaves. A few empty cells here and there might not be a big deal but as you can imagine, the appetite of an entire colony will soon result in huge areas of empty plant cells, which eventually kills the plant due to its inability to photosynthesize
  • An interesting phenomenon seen in spider mites is ARRHENOTOKY, which I explained using the term HAPLODIPLOIDY in my post about hymenopterans (Day 33). This means that males are produced from unfertilized eggs and females are produced from fertilized eggs
  • Studies have found that these mites can probably RECOGNIZE who they are related to in order to avoid inbreeding! When given a choice between two males in an experiment, one related and one not related them, females were more likely to mate with the one they were not related to, pointing to some mechanism for recognition
  • And finally, as I first mentioned in my aphid post (Day 30), this mite is the only animal species besides aphids known to produce CAROTENOIDS themselves. All other animals get these red/orange pigments from plants or algae they ingest. Two spotted spider mites can do it thanks to a gene transfer millions of years ago from fungi!
Labels:

Comments

Post a Comment

Popular posts from this blog

#13: Insect Legs

Litinsects #13: Insect Legs Insect legs can be as diverse as the animals themselves. Some are long and slender like a crane fly’s, some are short and hefty like a mole cricket’s. But what all insects share is the number and layout of those legs. Hexapods have 6 LEGS, a pair each of fore, mid, and hind legs that are made up of the same basic units. Starting closest to the body, they are:  (1) the coxa, which attaches the leg to the thorax  (2) the trochanter (3) the femur, which is oft en the thickest segment  (4) the tibia, often covered in tiny hairs (5) the tarsus, which contains 5 “pseudo-segments”  (6) the pretarsal claws, of which most insects have 2 on each leg The basic units of the leg always occur in this order but may be reduced or highly modified in some species to fit certain tasks such as running, digging, swimming, grasping, or jumping. This photo sums it up perfectly: from < https://wiki.bugwood.org/File:Insect...
Post a Comment
Read more

WELCOME: Social Distancing Entomology Course

All week I’ve been seeing videos and posts of the creative stuff people have been doing while social distancing, all the while thinking, what could I contribute to all the people sitting at home on social media all day?? Well this morning it hit me. I will do what I do best! And that is... drop some nerd knowledge on you all 🤓 Welcome to my social distancing ENTOMOLOGY COURSE!  Every day I will post an insect photo, most of which I’ve taken through my microscope, and explain about the insect group or the feature pictured. My hope is that you might learn something new about insects and maybe, just mayyyyybe, be a bit more fascinated and a bit less grossed out by the most diverse and arguably most successful group of animals to ever live... thanks for reading, stay tuned 🦋 🦟 🦗 🐞 🐜 🐛
Post a Comment
Read more

#22: Caterpillars

Litinsects #22: Caterpillars Since you are freshly familiar with metamorphosis from my last posts, I will today be talking about caterpillars 🐛 and some structures that change drastically in appearance from before to after metamorphosis: legs. Caterpillars are the worm-shaped larval stage of butterflies and moths. They have huge appetites; they mainly feed to grow and gain energy for their transformation into adulthood. In order to do this they need to get around, for which they use le gs because only adult stages have wings.  But insects only 3 pairs of legs, right? So where do all these extra legs come from all down the sides of their bodies?  Caterpillars have 3 pairs of TRUE LEGS, attached to their thorax, which are jointed and have little claws on the end. These legs are still present after metamorphosis, though they will have changed substantially Additionally, they usually have 2 to 5 pairs of PROLEGS, which are protrusions fr...
Post a Comment
Read more