Well we have the answer for you as we sell these guys in bulk to keep your lizard well fed.

Facts that you may not know about the care of horned lizards or just general information

• Horned Lizards are many times referred to as horned toads and are neither a frog or a toad but actually a kind of lizard.  They do however look warty like frogs.
• Some species of horned lizards can squirt blood out of their eyes. See this great video on it and interesting facts on Harvester ants Blood Squirting From Regal Horned Lizard Eye   There are at least four species that can shot blood to protect themselves from predators
• "Horned lizards (Phrynosoma) are a genus of the Phrynosomatidae family of lizards".  See Wikipedia for lots of information concerning these creatures and other interesting facts about other things they eat, reproduction and other great things.
•  No you may think that you can eat alot but but where horned lizards live in the wild ( typically the southwest USA) These guys have a voracious appetite.  These beasts can eat up to 100 or more harvester ants in a single day.  Not my type of feeder food but who am i to tell these guys what to have for dinner.
• Diet is extremely important for these 14 species of lizards ( 8 in the USA)  and a key ingredient is Western Harvester ants. The reason why Harvester ants are so important in the diet of horned lizards are the horned lizards convert these guys to formic acid. Dr. Richard Montanucci ( Maintenance & Propagation of Horned Lizards in Captivity, 1989 ). (To see see otheother papers Dr. Richard Montanucci has written see   Phylogenetic Analysis of the Horned Lizards (Phrynosomatidae: Phrynosoma): Evidence from Mitochondrial DNA and Morphology.  Without ants the lizards could not maintain the proper ph and flora which is vital to moving food and processing nutrients in the digestive track of many species.
• Without the proper ph and intestinal flora you are setting yourself up for some major problems which could result in the death of your reptile and you could have the whole digestive system is shut down.  Many times you will experience this after antibiotic medications are given, during illness, and/or when extremely under temperature, or due to exposure to a toxin or chemical. horned lizard healthy. The harvester ants contain a substance called formic acid which is also found in bees, wasps ( an ant with wings)as well as the scorpion species (Centruroides spp. found in the U.S.A.) .  Big scary things i know. Ants will inject formic acid as well as numerous other toxins and venoms, including apamin, melettin, phospholipases, hyaluronidases, histamine, and serotonin into other animals when trying to defend themselves from attack or protecting the queen of the ant colony or hill.  This initial sting can cause intense pain, swelling at the site of bite as well as anaphylactic shock from ant stings or pits as some may call it.  This protective behavior was first noted in 1671 by John Ray, the same guy who came up with the definition of the word species.  Anyway back to why Harvester ants are important to Horned lizards.  Without these creatures  the carboxylic acid cannot be the cornerstone of the amino acid chain.  This could lead to lead to impaction and a loss of immune function. The undigested prey will to lead to sepsis inside the bodies of your reptile
•   What else can formic acid help with?  Well it can provide proper hydration once ingested as well. 
• Everyone needs to eat and the ants provide some of the ideal sources of protein and EFA's. Essential fatty acids from diet may be directly deposited into adipose stores of predators which these animals need for proper growth.The ants get these from seeds, plants as well as other items they consume such as predators.   The Horned lizard then eats the ant and uses this for energy and protein.  The reason why this is better for the lizard then crickets and mealworms and other foods is do to chitin. Depending on the density of the chitan could cause problems with the storage of fat and food staying in the digestive tract and stomach of your lizard.  If you do not get rid of the stuff inside this can cause slow release of the fats inside which will cause problems. It has been shown that cricket extract prevented the increment of body weight by high-fat diet needs of rats in a paper  Dec 2004. 
  KEYWORDS
  Cricket • Gryllus bimaculatus • Lipid metabolism • So we basically want to stay with the thicker richer chitin as it does not break down as quickly.  This allows the horned lizard to get all of the nutrients from the harvester ants and process it efficiently.
• This is generally why Horned lizard care is typically reserved for the advanced herp and is so hard for many people to achieve a healthy reptile as they do not know what is vital to the well being of the animal.