Coral Island

To complete this you must catch with your Bug net or Ground and Flying insect traps 53 unique insects and donate them to the museum.

Once you reach Town Rank D you should develop the Sturdy Computer and Catching Component at Lings Lab. The component will show you the Forecast for insect and sea critters for that day and night. It will display what you have caught and what you have not as well as if you have donated it already or not. When you zoom in to the map it will show you the spawn locations for the critters (it shows spawn locations for the current time frame you are in Day/Night).

Lings Lab
Develop Equipment (Town Rank D)
Sturdy Computer (40k coins, Battery x10, Silver bar x10, Bronze ore x20, Scrap x100)
Catching Component (15k coins, Battery x5, Osmium ore x10, Gold ore x10, Wind essence x5)

The majority of insects you can easily catch with your Bug net especially an upgraded one. However, in both my playthroughs I seemed to never be able to catch three of them which I have listed below.

Rove beetle
Season: Fall/Winter
Location: Vineyard/Garden Lane
Weather: Sunny/Rain/Storm
Time: Night
Trap: Ground insect trap
Scent: Ground insect

Magnolia green jumper
Season: Spring/Summer
Location: Lake/Forest Farm
Weather: Rain/Storm
Time: Day/Night
Trap: Ground Insect trap
Scent: Ground insect

Blue morpho butterfly
Season: Summer
Location: Lake/Forest Farm
Weather: Windy
Time: Day
Trap: Flying insect trap
Scent: Flying insect

I highly recommend crafting and deploying Ground/Flying insect traps in the Lake and Farm Forest areas. Deploy Ground insect traps in the Vineyard. Also, when looking for the above-mentioned insects check your weather forecast for Windy and Rain days. then go inject the appropriate scents in to your deployed traps the day before the weather changes to greatly increase the probability of catching these insects.

Once you donate the 53rd unique insect to the museum the achievement will pop and you will be rewarded with the Moth suit.


Tips
In order to give you more real time each in game day to catch insects go into settings on the Game tab and change Game Time Speed to 50% which will slow in game time down to half giving you twice the amount of real time to play each in game day.

Upgrade your Bug net to copper, silver, gold, and Osmium. Provides a wider range of catching area when swinging your net.

Craft and deploy Ground/Flying insect traps especially in the Lake/Farm Forest/Vineyard areas.

Use scents in the traps to greatly increase chances of catching insects.

Inject scents in traps the day before Windy/Rainy days (use the weather channel on TV to get this information).