Golden Bugs
During his travels, Link will meet a young lass named Agitha in Castle Town who has an admiration for collecting insects. There are twelve species native to Hyrule, and they come in both male and female forms. Each time you deliver a new species of insect to Agitha, she'll reward you with rupees or a larger wallet. Every one of the bugs emit a soft glow, making them extremely easy to find at night. Furthermore, you'll hear a distinctive chime sound they make as you near.
Ant
Male
Where: Kakariko Village - Graveyard
The male ant is located on a tree to the right of the hole in the back of the graveyard.
Female
Where: Kakariko Village
Look for the female ant in the house just prior to the bomb shop on the west side of the village.
Beetle
Male
Where: Faron Province - Hyrule Field
This bug is located on a tree in the southern portion of Hyrule Field. The tree is positioned between two raised landmasses.
Female
Where: Faron Province - Hyrule Field
There's a tree on the western side of the field that's home to the female beetle (it's just west of the pond). Use the Gale Boomerang to pull her close.
Butterfly
Male
Where: Lanayru Province - Hyrule Field
Just south of the east entrance of Castle Town is a small flower patch containing this insect.
Female
Where: Lanayru Province - Hyrule Field
There's a vine-covered ledge just northeast of the east castle town exit. Grapple onto it with the Clawshot and snatch the insect in the flowers above.
Dayfly
Male
Where: Gerudo Desert
This guy's tough to find since he's not near any landmarks. Head to the exact center of the southern area and look for a glowing up north of the wooden barricades. It's easier to look for him at night, since his glow him easier to find.
Female
Where: Gerudo Desert
There are some trenches in the southeastern corner of Gerudo Desert (near where the missing part of bridge was). Search through them to find the female Dayfly.
Dragonfly
Male
Where: Zora's Domain
In the area with several waterfalls, climb the hill in the southwest to find the male Dragonfly.
Female
Where: Upper Zora's River
Look for the female dragonfly flying over the river right in front of the boat rental shop. Use the Gale Boomerang to grab it.
Grasshopper
Male
Where: Eldin Province - Hyrule Field
The male grasshopper can be found in Hyrule Field near entrance to Kakariko Village.
Female
Where: Eldin Province - Hyrule Field
Look for the female grasshopper in the northeast corner of the field. There aren't any land marks at night, so keep an eye out for her.
Ladybug
Male
Where: Lanayru Province - Hyrule Field
You can find the male Ladybug by a vine covered pillar in the field south of Castle Town.
Female
Where: Lanayru Province - Hyrule Field
The female ladybug hangs out near the group of three trees on the concrete entrance leading into Castle Town from the south.
Mantis
Male (I feel sorry for him)
Where: Lake Hylia - Great Bridge
The male Mantis hangs around the northern end of Lake Hylia's Great Bridge. He's generally in an impossible to reach location, so use the Gale Boomerang to nab him.
Female
Where: Lake Hylia - South of Great Bridge
There are several large tree trunks positioned south of the Great Bridge, but before the small wooden bridge. Use the Gale Boomerang to grab the female from high up on the east side.
Phasmid
Male
Where: Eldin Province - Hyrule Field
Check out the interior of the southern arch on Eldin Bridge to find this bug. Eldin Bridge is in the northwest corner of Hyrule Field.
Female
Where: Eldin Province - Hyrule Field
The female Phasmid is located on a cliff ledge to the north of Eldin Bridge. Clawshot onto it via the tile and follow it to the insect.
Pill Bug
Male
Where: Kakariko Gorge
The Pill Bug can be found right by the south end of bridge.
Female
Where: Kakariko Gorge
The female Pill Bug is located by the flowers the southwest corner, north of the bridge.
Snail
Male
Where: Sacred Grove
You can find the Male snail inside the entrance of the southwest alcove in the Sacred Grove.
Female
Where: Temple of Time
Enter the Temple of Time from the Sacred Grove to find the female snail on the west side of the staircase.
Stag Beetle
Male
Where: Lanayru Province - Hyrule Field
This insect can be found near a tree on the east side of Hyrule Field (opposite of the bridge).
Female
Where: Lanayru Province - Hyrule Field
Among the lower portion of the rocky area in the north part of this field, there's an insect hiding above a bombable entrance.