8 hours of collecting data on 15 spotted tigerferns:

Bug # 1 Seen: 19 (6 %) common Blue Butterfly
Bug # 2 Seen: 26 (8 %) common Mission Blue Butterfly
Bug # 4 Seen: 17 (5 %) common Black Moth
Bug # 5 Seen: 4 (1 %) uncommon Pale Moth
Bug # 6 Seen: 3 (1 %) uncommon Lapis Butterfly
Bug # 7 Seen: 6 (2 %) uncommon Lemon Moth
Bug # 9 Seen: 5 (2 %) rare Plum Butterfly
Bug #10 Seen: 4 (1 %) rare Cherry Butterfly
Bug #13 Seen: 25 (8 %) common Green Beetle
Bug #14 Seen: 17 (5 %) common Brown Bug
Bug #15 Seen: 19 (6 %) common Ladybug
Bug #17 Seen: 4 (1 %) uncommon Hiding Beetle
Bug #18 Seen: 4 (1 %) uncommon Zebra Beetle
Bug #19 Seen: 7 (2 %) uncommon Cockroach
Bug #21 Seen: 2 (1 %) rare Ebony Scarab
Bug #22 Seen: 6 (2 %) rare Fire Scarab
Bug #25 Seen: 20 (6 %) common Blue Dragonfly
Bug #26 Seen: 17 (5 %) common Pink Dragonfly
Bug #28 Seen: 14 (4 %) common Emerald Dragonfly
Bug #29 Seen: 3 (1 %) uncommon Dart Dragonfly
Bug #30 Seen: 5 (2 %) uncommon Fragile Dragonfly
Bug #31 Seen: 5 (2 %) uncommon Ghost Dragonfly
Bug #33 Seen: 5 (2 %) rare Fire Dragonfly
Bug #35 Seen: 7 (2 %) rare Earth Dragonfly
Bug #38 Seen: 18 (6 %) common Yellow Spider
Bug #39 Seen: 26 (8 %) common Brown Spider
Bug #40 Seen: 15 (5 %) common Spotted Spider
Bug #41 Seen: 3 (1 %) uncommon Pearly Spider
Bug #42 Seen: 2 (1 %) uncommon Limelike Spider
Bug #44 Seen: 4 (1 %) uncommon Cricket Spider
Bug #45 Seen: 3 (1 %) rare Bumpy Spider
Bug #46 Seen: 1 (0 %) rare Jade Spider

Bug number 27, the common Tiger Dragonfly, is conspicuously absent. One thought is that it is attracted to Tigerferns but needs a higher tier of flower than spotted. A better guess is that it is not attracted to Tigerferns, since DW reports always collecting this insect in new games, well before tier 4 is ever reached.

No progress on the common shiny blue beetle either. So basically, no progress \:\)

So it still remains a mystery.

addendum: with the following group of starter plants:
spotted reptans
bluestar maranta
citrus maranta
citrus maple
citrus astera
fourpetal ball cactus
citrus ball cactus
spotted ball cactus
jalapa ball cactus
both the common shiny blue beetle and the common Tiger Dragonfly made an appearance. just have to figure out which foliage or flower is responsible.