Let him hunt in his tank , a few fast moving bugs at a time , let him watch you give them to him, he'll soon learn to watch you in anticipation of yummy bugs you will be giving him.
When he looses interest in hunting them - he's full.
If you have BSFL or silkworms ,they can be left in a dish for him to grase on at his leisure.
I use this set up for my BSFL -
viewtopic.php?f=75&t=239661&p=1837017#p1837017
BTW : I can see some obvious issues with your setup
1) dial type analog thermometer - these are hopelessly inaccurate , better off replacing with a few of these digital thermometers =
https://www.ebay.com.au/itm/Aquarium-LCD-Electronic-Digital-Thermometer-Fish-Tank-Water-Detector-Practica-BU/252762165947?_trksid=p2385738.c100677.m4598&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20160908110712%26meid%3D6ac464a2a1b24339be32c744b2ff5cf9%26pid%3D100677%26rk%3D2%26rkt%3D15%26sd%3D201577608563
2) compact UVB globe mounted ontop of the very fine mesh lid
>> issues here are , it's likely not strong enough , needs to be AT LEAST a 25W UVB200 (10% UVB)
>> too far from the dragon's basking spot to give him sufficient UVA and UVB exposure , see this for working out appropriate distances :
viewtopic.php?f=34&t=235611 , ie for a 25W UVB200 in a reflector hood or dome , the appropriate distance is NOT MORE THAN 8 inches to the basking spot (gives 180 - 200 microW UVB / sq.cm at the basking spot)
>> the mesh will be blocking in excess of 40% of the UV produced by the compact globe (or the MVB if you are using an MVB as the basking globe / UV source).
Easy fix is to invest in ExoTerra NanoHood
http://www.exo-terra.com/en/products/compact_top.php
(for one compact globe) and mount this UNDER the mesh lid ==> will instantly double the UV the dragon can enjoy. This can mounted very easily using cable ties or even a couple handy length of mono-fishing line or wool or string (poked through the mesh and wrapped around each of the nanohood.
Even better if you have the money , upgrade to a t5ho reflector hood about 2/3 the length of the viv and a 12% UVB t5ho tube to match and mount these under the mesh with one end adjacent to the basking globe.
3) mesh hammock - these are risky for dragons because they pose a snag risk for their curved nails which can easy become caught in the mesh and a panicking struggling dragon can easily do very serious injuries to an arm or leg if it can't get a snagged nail loose.